Recommended Infection-

Control Practices for Dentistry

 

Summary

This document updates previously published CDC recommendations for infection-control practices in dentistry to reflect new data, materials, technology, and equipment. When implemented, these recommendations should reduce the risk of disease transmission in the dental environment, from patient to dental health-care worker (DHCW), from DHCW to patient, and from patient to patient. Based on principles of infection control, the document delineates specific recommendations related to vaccination of DHCWs; protective attire and barrier techniques; handwashing and care of hands; the use and care of sharp instruments and needles; sterilization or disinfection of instruments; cleaning and disinfection of the dental unit and environmental surfaces; disinfection and the dental laboratory; use and care of handpieces, antiretraction valves, and other intraoral dental devices attached to air and water lines of dental units; single-use disposable instruments; the handling of biopsy specimens; use of extracted teeth in dental educational settings; disposal of waste materials; and implementation of recommendations.

Introduction

This document updates previously published CDC recommendations for infection-control practices for dentistry (1-3) and offers guidance for reducing the risks of disease transmission among dental health-care workers (DHCWs) and their patients. Although the principles of infection control remain unchanged, new technologies, materials, equipment, and data require continuous evaluation of current infection-control practices. The unique nature of most dental procedures, instrumentation, and patient-care settings also may require specific strategies directed to the prevention of transmission of pathogens among DHCWs and their patients. Recommended infection-control practices are applicable to all settings in which dental treatment is provided. These recommended practices should be observed in addition to the practices and procedures for worker protection required by the Occupational Safety and Health Administration (OSHA) final rule on Occupational Exposure to Bloodborne Pathogens (29 CFR 1910.1030), which was published in the Federal Register on December 6, 1991 (4).

Dental patients and DHCWs may be exposed to a variety of microorganisms via blood or oral or respiratory secretions. These microorganisms may include cytomegalovirus, hepatitis B virus (HBV), hepatitis C virus (HCV), herpes simplex virus types 1 and 2, human immunodeficiency virus (HIV), Mycobacterium tuberculosis, staphylococci, streptococci, and other viruses and bacteria _ specifically, those that infect the upper respiratory tract. Infections may be transmitted in the dental operatory through several routes, including direct contact with blood, oral fluids, or other secretions; indirect contact with contaminated instruments, operatory equipment, or environmental surfaces; or contact with airborne contaminants present in either droplet spatter or aerosols of oral and respiratory fluids. Infection via any of these routes requires that all three of the following conditions be present (commonly referred to as "the chain of infection"): a susceptible host; a pathogen with sufficient infectivity and numbers to cause infection; and a portal through which the pathogen may enter the host. Effective infection-control strategies are intended to break one or more of these "links" in the chain, thereby preventing infection.

A set of infection-control strategies common to all health-care delivery settings should reduce the risk of transmission of infectious diseases caused by bloodborne pathogens such as HBV and HIV (2,5-10). Because all infected patients cannot be identified by medical history, physical examination, or laboratory tests, CDC recommends that blood and body fluid precautions be used consistently for all patients (2,5 ). This extension of blood and body fluid precautions, referred to as "universal precautions," must be observed routinely in the care of all dental patients (2). In addition, specific actions have been recommended to reduce the risk of tuberculosis transmission in dental and other ambulatory health-care facilities (11).

Definitions

"Blood" means human blood, human blood components, and products made from human blood.

"Bloodborne pathogens" means pathogenic microorganisms that are present in human blood and can cause disease in humans. These pathogens include, but are not limited to, hepatitis B virus (HBV) and human immunodeficiency virus (HIV).

"Contaminated" means the presence or the reasonably anticipated presence of blood or other potentially infectious materials on a surface or in or on an item.

"Contaminated laundry" means laundry which has been soiled with blood or other potentially infectious materials or may contain sharps.

"Contaminated sharps" means any contaminated object that can penetrate the skin including, but not limited to, needles, scalpels, broken glass, broken capillary tubes, and exposed ends of dental wires.

"Decontamination" means the use of physical or chemical means to remove, inactivate, or destroy bloodborne pathogens on a surface or item to the point where they are no longer capable of transmitting infectious particles and the surface or item is rendered safe for handling, use, or disposal.

"Exposure incident" means a specific eye, mouth, other mucous membrane, non-intact skin, or parenteral contact with blood or other potentially infectious materials that results from the performance of an employee's duties.

"Handwashing facilities" means a facility providing an adequate supply of running potable water, soap and single use towels or hot air drying machines.

"Occupational exposure" means reasonably anticipated skin, eye, mucous membrane, or parenteral contact with blood or other potentially infectious materials that may result from the performance of an employee's duties.

"One-hand technique" means procedure wherein the needle of a reusable syringe is capped in a sterile manner during use. The technique employed shall require the use of only the hand holding the syringe so that the free hand is not exposed to the uncapped needle.

"Other potentially infectious materials" means: The following human body fluids: semen, vaginal secretions, cerebrospinal fluid, synovial fluid, pleural fluid, pericardial fluid, peritoneal fluid, amniotic fluid, saliva in dental procedures, any other body fluid that is visibly contaminated with blood such as saliva or vomitus, and all body fluids in situations where it is difficult or impossible to differentiate between body fluids such as emergency response;

Any unfixed tissue or organ (other than intact skin) from a human (living or dead); and
HIV-containing cell or tissue cultures, organ cultures, and HIV-or HBV-containing culture medium or other solutions; and blood, organs, or other tissues from experimental animals infected with HIV or HBV.

"Parenteral" means piercing mucous membranes or the skin barrier through such events as needlesticks, human bites, cuts, and abrasions.

"Personal protective equipment" is specialized clothing or equipment worn or used by an employee for protection against a hazard. General work clothes (e.g., uniforms, pants, shirts or blouses) not intended to function as protection against a hazard are not considered to be personal protective equipment.

Regulated waste" means waste that is any of the following:

  1. Liquid or semi-liquid blood or OPIM;

     

  2. Contaminated items that:
    1. Contain liquid or semi-liquid blood, or are caked with dried blood or OPIM; and
    2. Are capable of releasing these materials when handled or compressed.
  3. Contaminated sharps.
  4. Pathological and microbiological wastes containing blood or OPIM.
"Sharp" means any object that can be reasonably anticipated to penetrate the skin or any other part of the body, and to result in an exposure incident, including, but not limited to, needle devices, scalpels, lancets, broken glass, broken capillary tubes, exposed ends of dental wires and dental knives, drills and burs.

"Sharps injury" means any injury caused by a sharp, including, but not limited to, cuts, abrasions, or needlesticks.

"Source individual" means any individual, living or dead, whose blood or other potentially infectious materials may be a source of occupational exposure to the employee.

"Sterilize" means the use of a physical or chemical procedure to destroy all microbial life including highly resistant bacterial endospores.

"Universal precautions" is an approach to infection control. According to the concept of universal precautions, all human blood and certain human body fluids are treated as if known to be infectious for HIV, HBV, and other bloodborne pathogens.

"Work practice controls" means controls that reduce the likelihood of exposure by altering the manner in which a task is performed (e.g., prohibiting recapping of needles by a two-handed technique).

Confirmed Transmission of HBV and HIV and Dentistry

Although the possibility of transmission of bloodborne infections from DHCWs to patients is considered to be small (12- 15), precise risks have not been quantified in the dental setting by carefully designed epidemiologic studies. Reports published from 1970 through 1987 indicate nine clusters in which patients were infected with HBV associated with treatment by an infected DHCW (16-25). In addition, transmission of HIV to six patients of a dentist with acquired immunodeficiency syndrome has been reported (26,27). Transmission of HBV from dentists to patients has not been reported since 1987, possibly reflecting such factors as incomplete ascertainment and reporting, increased adherence to universal precautions including routine glove use by dentists and increased levels of immunity due to use of hepatitis B vaccine. However, isolated sporadic cases of infection are more difficult to link with a health-care worker than are outbreaks involving multiple patients. For both HBV and HIV, the precise event or events resulting in transmission of infection in the dental setting have not been determined; epidemiologic and laboratory data indicate that these infections probably were transmitted from the DHCWs to patients, rather than from one patient to another (26,28). Patient-to-patient transmission of bloodborne pathogens has been reported, however, in several medical settings (29-31).

Vaccines For Dental Health-Care Workers

Although HBV infection is uncommon among adults in the United States (1%-2%), serologic surveys have indicated that 10%-30% of health-care or dental workers show evidence of past or present HBV infection (6,32). The OSHA bloodborne pathogens final rule requires that employers make hepatitis B vaccinations available without cost to their employees who may be exposed to blood or other infectious materials (4). In addition, CDC recommends that all workers, including DHCWs, who might be exposed to blood or blood-contaminated substances in an occupational setting be vaccinated for HBV (6-8). DHCWs also are at risk for exposure to and possible transmission of other vaccine-preventable diseases (33); accordingly, vaccination against influenza, measles, mumps, rubella, and tetanus may be appropriate for DHCWs.

Protective Attire and Barrier Techniques

For protection of personnel and patients in dental-care settings, medical gloves (latex or vinyl) always must be worn by DHCWs when there is potential for contacting blood, blood-contaminated saliva, or mucous membranes (1,2,4-6). Nonsterile gloves are appropriate for examinations and other nonsurgical procedures (5); sterile gloves should be used for surgical procedures. Before treatment of each patient, DHCWs should wash their hands and put on new gloves; after treatment of each patient or before leaving the dental operatory, DHCWs should remove and discard gloves, then wash their hands. DHCWs always should wash their hands and reglove between patients. Surgical or examination gloves should not be washed before use; nor should they be washed, disinfected, or sterilized for reuse. Washing of gloves may cause "wicking" (penetration of liquids through undetected holes in the gloves) and is not recommended (5). Deterioration of gloves may be caused by disinfecting agents, oils, certain oil-based lotions, and heat treatments, such as autoclaving.

Chin-length plastic face shields or surgical masks and protective eyewear should be worn when splashing or spattering of blood or other body fluids is likely, as is common in dentistry (2,5,6,34,35). When a mask is used, it should be changed between patients or during patient treatment if it becomes wet or moist. Face shields or protective eyewear should be washed with an appropriate cleaning agent and, when visibly soiled, disinfected between patients.

Protective clothing such as reusable or disposable gowns, laboratory coats, or uniforms should be worn when clothing is likely to be soiled with blood or other body fluids (2,5,6). Reusable protective clothing should be washed, using a normal laundry cycle, according to the instructions of detergent and machine manufacturers. Protective clothing should be changed at least daily or as soon as it becomes visibly soiled (9). Protective garments and devices (including gloves, masks, and eye and face protection) should be removed before personnel exit areas of the dental office used for laboratory or patient-care activities.

Impervious-backed paper, aluminum foil, or plastic covers should be used to protect items and surfaces (e.g., light handles or x-ray unit heads) that may become contaminated by blood or saliva during use and that are difficult or impossible to clean and disinfect. Between patients, the coverings should be removed (while DHCWs are gloved), discarded, and replaced (after ungloving and washing of hands) with clean material.

Appropriate use of rubber dams, high-velocity air evacuation, and proper patient positioning should minimize the formation of droplets, spatter, and aerosols during patient treatment. In addition, splash shields should be used in the dental laboratory.

Personal Protective Equipment (PPE)

DHCWs must wear protective attire such as eye wear or a chin-length shield, disposable gloves, a disposable surgical quality mask, and protective clothing when performing procedures capable of causing splash, spatter, or other contact with body fluids, and/or mucous membranes. Protective attire must also be worn when touching items or surfaces that may be contaminated with these fluids, and during other activities that pose a risk of exposure to blood, saliva or tissue.

Dental clinical personnel must wear protective attire such as eye wear or a chin-length shield, disposable gloves, a disposable surgical quality mask, and protective clothing when performing procedures capable of causing splash, spatter, contact with body fluids, mucous membranes, or touching items or surfaces that may be contaminated with these fluids. Protective attire also must be worn during other activities that require handling items contaminated with patient secretions that create a potential for exposure to blood, saliva or tissue.

Gloves are single use items and must not be reused. Single use gloves may not be washed, disinfected or sterilized. They may be rinsed with water only to remove excess powder. Torn or compromised gloves must be replaced immediately. Latex, vinyl or other disposable medical quality gloves may be used for patient exams and procedures. Plastic or foodhandlers' gloves may be worn over contaminated treatment gloves (overgloving) to prevent contamination of clean objects handled during treatment. These overgloves may never be used alone as a hand barrier, or for intraoral patient care procedures. Overgloves must be handled carefully to avoid contamination during handling with contaminated procedure gloves. If overgloves are not used, contaminated procedure gloves should be removed before leaving chairside during patient care and replaced with new gloves upon returning to patient care. Hands must be washed after glove removal and before re-gloving.

Surgical masks that have at least 95% filtration efficiency for particles 3-5 micron in diameter must be worn whenever splash or spatter is anticipated. Masks should be changed for every patient or more often, particularly if heavy spatter is generated during treatment. Some literature suggests masks should be worn a maximum of 20 minutes in areas of high humidity, and a maximum of 60 minutes in dry climates. Masks should be handled by touching the periphery only, avoiding handling of the body of the mask. Masks should not contact the mouth while being worn as the moisture generated will decrease the mask filtration efficiency. A mask should be selected that conforms well to the shape of the face. A faceshield does not substitute for a surgical mask.

Protective eye wear must have solid side-shields and be decontaminated by immersion in a cleaning agent between patients. A faceshield may substitute for protective eye wear. If protective eyewear or a faceshield is used to protect against damage from solid projectiles, the protective eyewear should meet American National Standards Institute (ANSI) Occupational and Educational Eye and Face Protection Standard (Z87.1-1989) and be clearly marked as such.

Protective clothing must have a high neck and protect the arms if splash and spatter are reasonably anticipated. Cotton or cotton/polyester or disposable clinic jackets or lab coats are usually satisfactory attire for routine dental procedures. The type and characteristics of protective clothing depend on the type of exposure anticipated. Gowns or jackets worn as protective attire should be changed at least daily, or more often if visibly soiled. Protective gowns or covers must be removed before leaving the work area. Protective attire may not be taken home and washed by employees. It may be laundered in the office if equipment is available and universal precautions are followed for handling and laundering contaminated attire. Contaminated linens transported away from the office for laundering should be in appropriate bags to prevent leaking, with a biohazard label or appropriately color-coded, unless the laundry facility employees practice universal precautions in the handling of all laundry. Disposable gowns may be used but must be discarded daily, or more often if visibly soiled.

Utility gloves that are puncture-resistant, a mask, protective clothing and protective eyewear must be worn when handling and cleaning contaminated instruments, when performing operatory cleanup, and for surface cleaning and disinfecting. Utility gloves must be discarded if their barrier properties become compromised. Utility gloves, protective eye wear or face shields, and masks must be worn when mixing and/or using chemical sterilants or disinfectants. Used utility gloves must be considered contaminated and handled appropriately until properly disinfected or sterilized. 

NOTE: Along with the increased use of latex gloves for infection control purposes has been an increased incidence of latex allergies and other sensitivities. Certain individuals are considered to be at an increased risk of latex sensitivity. These individuals include persons who have had multiple surgeries (especially involving the placement of rubber tubes or drains), spina bifida patients, health care workers, and individuals with other documented allergies. Medical histories should include questions which may alert the DHCW that a patient is latex-sensitive. If a person is found to be sensitive to latex, precautions such as non-latex gloves, non-latex rubber dams, and avoidance of any other latex-containing products should be implemented in the treatment of those patients. Latex-sensitive patients should also be scheduled at the beginning of the day to minimize exposure to latex residue and powder.

DHCWs who experience symptoms consistent with sensitivity including skin rash, itching, or wheezing should seek the advice of a qualified medical professional for diagnosis of the symptoms. Because a variety of materials may be responsible for the sensitivity, including resin materials which may permeate the gloves, self-diagnosis is ill-advised and could increase the risk of a serious allergic response.

Handwashing and Care of Hands

DHCWs should wash their hands before and after treating each patient (i.e., before glove placement and after glove removal) and after barehanded touching of inanimate objects likely to be contaminated by blood, saliva, or respiratory secretions (2,5,6,9). Hands should be washed after removal of gloves because gloves may become perforated during use, and DHCWs' hands may become contaminated through contact with patient material. Soap and water will remove transient microorganisms acquired directly or indirectly from patient contact (9); therefore, for many routine dental procedures, such as examinations and nonsurgical techniques, handwashing with plain soap is adequate. For surgical procedures, an antimicrobial surgical handscrub should be used (10).

When gloves are torn, cut, or punctured, they should be removed as soon as patient safety permits. DHCWs then should wash their hands thoroughly and reglove to complete the dental procedure. DHCWs who have exudative lesions or weeping dermatitis, particularly on the hands, should refrain from all direct patient care and from handling dental patient-care equipment until the condition resolves (12). Guidelines addressing management of occupational exposures to blood and other fluids to which universal precautions apply have been published previously (6-8,36).

Use and Care of Sharp Instruments and Needles

Sharp items (e.g., needles, scalpel blades, wires) contaminated with patient blood and saliva should be considered as potentially infective and handled with care to prevent injuries (2,5,6).

Used needles should never be recapped or otherwise manipulated utilizing both hands, or any other technique that involves directing the point of a needle toward any part of the body (2,5,6). Either a one-handed "scoop" technique or a mechanical device designed for holding the needle sheath should be employed. Used disposable syringes and needles, scalpel blades, and other sharp items should be placed in appropriate puncture-resistant containers located as close as is practical to the area in which the items were used (2,5,6).

Bending or breaking of needles before disposal requires unnecessary manipulation and thus is not recommended.

Before attempting to remove needles from nondisposable aspirating syringes, DHCWs should recap them to prevent injuries. Either of the two acceptable techniques may be used. For procedures involving multiple injections with a single needle, the unsheathed needle should be placed in a location where it will not become contaminated or contribute to unintentional needlesticks between injections. If the decision is made to recap a needle between injections, a one-handed "scoop" technique or a mechanical device designed to hold the needle sheath is recommended.

Sterilization or Disinfection of Instrument

Indications for Sterilization or Disinfection of Dental Instruments

As with other medical and surgical instruments, dental instruments are classified into three categories _ critical, semicritical, or noncritical _ depending on their risk of transmitting infection and the need to sterilize them between uses (9,37-40). Each dental practice should classify all instruments as follows:

Critical. Surgical and other instruments used to penetrate soft tissue or bone are classified as critical and should be sterilized after each use. These devices include forceps, scalpels, bone chisels, scalers, and burs.

Semicritical. Instruments such as mirrors and amalgam condensers that do not penetrate soft tissues or bone but contact oral tissues are classified as semicritical. These devices should be sterilized after each use. If, however, sterilization is not feasible because the instrument will be damaged by heat, the instrument should receive, at a minimum, high-level disinfection.

Noncritical. Instruments or medical devices such as external components of x-ray heads that come into contact only with intact skin are classified as noncritical. Because these noncritical surfaces have a relatively low risk of transmitting infection, they may be reprocessed between patients with intermediate-level or low-level disinfection (see Cleaning and Disinfection of Dental Unit and Environmental Surfaces) or detergent and water washing, depending on the nature of the surface and the degree and nature of the contamination (9,38).

Methods of Sterilization or Disinfection of Dental Instruments

Before sterilization or high-level disinfection, instruments should be cleaned thoroughly to remove debris. Persons involved in cleaning and reprocessing instruments should wear heavy-duty (reusable utility) gloves to lessen the risk of hand injuries. Placing instruments into a container of water or disinfectant/detergent as soon as possible after use will prevent drying of patient material and make cleaning easier and more efficient. Cleaning may be accomplished by thorough scrubbing with soap and water or a detergent solution, or with a mechanical device (e.g., an ultrasonic cleaner). The use of covered ultrasonic cleaners, when possible, is recommended to increase efficiency of cleaning and to reduce handling of sharp instruments.

All critical and semicritical dental instruments that are heat stable should be sterilized routinely between uses by steam under pressure (autoclaving), dry heat, or chemical vapor, following the instructions of the manufacturers of the instruments and the sterilizers. Critical and semicritical instruments that will not be used immediately should be packaged before sterilization.

Proper functioning of sterilization cycles should be verified by the periodic use (at least weekly) of biologic indicators (i.e., spore tests) (3,9). Heat-sensitive chemical indicators (e.g., those that change color after exposure to heat) alone do not ensure adequacy of a sterilization cycle but may be used on the outside of each pack to identify packs that have been processed through the heating cycle. A simple and inexpensive method to confirm heat penetration to all instruments during each cycle is the use of a chemical indicator inside and in the center of either a load of unwrapped instruments or in each multiple instrument pack (41); this procedure is recommended for use in all dental practices. Instructions provided by the manufacturers of medical/dental instruments and sterilization devices should be followed closely.

In all dental and other health-care settings, indications for the use of liquid chemical germicides to sterilize instruments (i.e., "cold sterilization") are limited. For heat-sensitive instruments, this procedure may require up to 10 hours of exposure to a liquid chemical agent registered with the U.S. Environmental Protection Agency (EPA) as a "sterilant/disinfectant." This sterilization process should be followed by aseptic rinsing with sterile water, drying, and, if the instrument is not used immediately, placement in a sterile container.

EPA-registered "sterilant/disinfectant" chemicals are used to attain high-level disinfection of heat-sensitive semicritical medical and dental instruments. The product manufacturers' directions regarding appropriate concentration and exposure time should be followed closely. The EPA classification of the liquid chemical agent (i.e., "sterilant/disinfectant") will be shown on the chemical label. Liquid chemical agents that are less potent than the "sterilant/disinfectant" category are not appropriate for reprocessing critical or semicritical dental instruments.

Cleaning and Disinfection of Dental Unit and Environmental Surfaces

After treatment of each patient and at the completion of daily work activities, countertops and dental unit surfaces that may have become contaminated with patient material should be cleaned with disposable toweling, using an appropriate cleaning agent and water as necessary. Surfaces then should be disinfected with a suitable chemical germicide.

A chemical germicide registered with the EPA as a "hospital disinfectant" and labeled for "tuberculocidal" (i.e., mycobactericidal) activity is recommended for disinfecting surfaces that have been soiled with patient material. These intermediate-level disinfectants include phenolics, iodophors, and chlorine-containing compounds. Because mycobacteria are among the most resistant groups of microorganisms, germicides effective against mycobacteria should be effective against many other bacterial and viral pathogens (9,38-40,42). A fresh solution of sodium hypochlorite (household bleach) prepared daily is an inexpensive and effective intermediate-level germicide. Concentrations ranging from 500 to 800 ppm of chlorine (a 1:100 dilution of bleach and tap water or 1/4 cup of bleach to 1 gallon of water) are effective on environmental surfaces that have been cleaned of visible contamination. Caution should be exercised, since chlorine solutions are corrosive to metals, especially aluminum.

Low-level disinfectants EPA-registered "hospital disinfectants" that are not labeled for "tuberculocidal" activity (e.g., quaternary ammonium compounds) are appropriate for general housekeeping purposes such as cleaning floors, walls, and other housekeeping surfaces. Intermediate- and low-level disinfectants are not recommended for reprocessing critical or semicritical dental instruments.

Disinfection and the Dental Laboratory

Laboratory materials and other items that have been used in the mouth (e.g., impressions, bite registrations, fixed and removable prostheses, orthodontic appliances) should be cleaned and disinfected before being manipulated in the laboratory, whether an on-site or remote location (43). These items also should be cleaned and disinfected after being manipulated in the dental laboratory and before placement in the patient's mouth (2). Because of the increasing variety of dental materials used intraorally, DHCWs are advised to consult with manufacturers regarding the stability of specific materials relative to disinfection procedures. A chemical germicide having at least an intermediate level of activity (i.e., "tuberculocidal hospital disinfectant") is appropriate for such disinfection. Communication between dental office and dental laboratory personnel regarding the handling and decontamination of supplies and materials is important.

Use and Care of Handpieces, Antiretraction Valves, and Other Intraoral Dental Devices Attached to Air and Water Lines of Dental Units

Routine between-patient use of a heating process capable of sterilization (i.e., steam under pressure {autoclaving}, dry heat, or heat/chemical vapor) is recommended for all high-speed dental handpieces, low-speed handpiece components used intraorally, and reusable prophylaxis angles. Manufacturers' instructions for cleaning, lubrication, and sterilization procedures should be followed closely to ensure both the effectiveness of the sterilization process and the longevity of these instruments. According to manufacturers, virtually all high-speed and low-speed handpieces in production today are heat tolerant, and most heat-sensitive models manufactured earlier can be retrofitted with heat-stable components.

Internal surfaces of high-speed handpieces, low-speed handpiece components, and prophylaxis angles may become contaminated with patient material during use. This retained patient material then may be expelled intraorally during subsequent uses (44-46). Restricted physical access _ particularly to internal surfaces of these instruments_ limits cleaning and disinfection or sterilization with liquid chemical germicides. Surface disinfection by wiping or soaking in liquid chemical germicides is not an acceptable method for reprocessing high-speed handpieces, low-speed handpiece components used intraorally, or reusable prophylaxis angles.

Because retraction valves in dental unit water lines may cause aspiration of patient material back into the handpiece and water lines, antiretraction valves (one-way flow check valves) should be installed to prevent fluid aspiration and to reduce the risk of transfer of potentially infective material (47). Routine maintenance of antiretraction valves is necessary to ensure effectiveness; the dental unit manufacturer should be consulted to establish an appropriate maintenance routine.

High-speed handpieces should be run to discharge water and air for a minimum of 20-30 seconds after use on each patient. This procedure is intended to aid in physically flushing out patient material that may have entered the turbine and air or water lines (46). Use of an enclosed container or high-velocity evacuation should be considered to minimize the spread of spray, spatter, and aerosols generated during discharge procedures.

Additionally, there is evidence that overnight or weekend microbial accumulation in water lines can be reduced substantially by removing the handpiece and allowing water lines to run and to discharge water for several minutes at the beginning of each clinic day (48). Sterile saline or sterile water should be used as a coolant/irrigator when surgical procedures involving the cutting of bone are performed.

Other reusable intraoral instruments attached to, but removable from, the dental unit air or water lines — such as ultrasonic scaler tips and component parts and air/water syringe tips — should be cleaned and sterilized after treatment of each patient in the same manner as handpieces, which was described previously. Manufacturers' directions for reprocessing should be followed to ensure effectiveness of the process as well as longevity of the instruments.

Some dental instruments have components that are heat sensitive or are permanently attached to dental unit water lines. Some items may not enter the patient's oral cavity, but are likely to become contaminated with oral fluids during treatment procedures, including, for example, handles or dental unit attachments of saliva ejectors, high-speed air evacuators, and air/water syringes. These components should be covered with impervious barriers that are changed after each use or, if the surface permits, carefully cleaned and then treated with a chemical germicide having at least an intermediate level of activity. As with high-speed dental handpieces, water lines to all instruments should be flushed thoroughly after the treatment of each patient; flushing at the beginning of each clinic day also is recommended.

Single-Use Disposable Instruments

Single-use disposable instruments (e.g., prophylaxis angles; prophylaxis cups and brushes; tips for high-speed air evacuators, saliva ejectors, and air/water syringes) should be used for one patient only and discarded appropriately. These items are neither designed nor intended to be cleaned, disinfected, or sterilized for reuse.

Handling of Biopsy Specimens

In general, each biopsy specimen should be put in a sturdy container with a secure lid to prevent leaking during transport. Care should be taken when collecting specimens to avoid contamination of the outside of the container. If the outside of the container is visibly contaminated, it should be cleaned and disinfected or placed in an impervious bag (49).

Use of Extracted Teeth in Dental Educational Settings

Extracted teeth used for the education of DHCWs should be considered infective and classified as clinical specimens because they contain blood. All persons who collect, transport, or manipulate extracted teeth should handle them with the same precautions as a specimen for biopsy (2). Universal precautions should be adhered to whenever extracted teeth are handled; because preclinical educational exercises simulate clinical experiences, students enrolled in dental educational programs should adhere to universal precautions in both preclinical and clinical settings. In addition, all persons who handle extracted teeth in dental educational settings should receive hepatitis B vaccine (6-8).

Before extracted teeth are manipulated in dental educational exercises, the teeth first should be cleaned of adherent patient material by scrubbing with detergent and water or by using an ultrasonic cleaner. Teeth should then be stored, immersed in a fresh solution of sodium hypochlorite (household bleach diluted 1:10 with tap water) or any liquid chemical germicide suitable for clinical specimen fixation (50).

Persons handling extracted teeth should wear gloves. Gloves should be disposed of properly and hands washed after completion of work activities. Additional personal protective equipment (e.g., face shield or surgical mask and protective eyewear) should be worn if mucous membrane contact with debris or spatter is anticipated when the specimen is handled, cleaned, or manipulated. Work surfaces and equipment should be cleaned and decontaminated with an appropriate liquid chemical germicide after completion of work activities (37,38,40,51).

The handling of extracted teeth used in dental educational settings differs from giving patients their own extracted teeth. Several states allow patients to keep such teeth, because these teeth are not considered to be regulated (pathologic) waste (52) or because the removed body part (tooth) becomes the property of the patient and does not enter the waste system (53).

Disposal of Waste Materials

Blood, suctioned fluids, or other liquid waste may be poured carefully into a drain connected to a sanitary sewer system. Disposable needles, scalpels, or other sharp items should be placed intact into puncture-resistant containers before disposal. Solid waste contaminated with blood or other body fluids should be placed in sealed, sturdy impervious bags to prevent leakage of the contained items. All contained solid waste should then be disposed of according to requirements established by local, state, or federal environmental regulatory agencies and published recommendations (9,49).

The Use and Handling of Toothbrushes

Toothbrushes can become contaminated with blood and saliva, thus potentially could transmit infections. In schools, day-care programs, and other institutional settings, common sense and proper hygiene practices should be the primary considerations in the use and care of toothbrushes. The following hygienic measures are recommended:

 
 Each child should have his/her own toothbrush, clearly marked with identification. No sharing or borrowing should be allowed. A pea-sized (or smaller) amount of · fluoride should be dispensed on a dry toothbrush.
 Following use, toothbrushes should be allowed to air-dry and stored so they will cannot contact each other. Paper cups used by children for rinsing, following brushing, should be disposed of properly.
 Toothbrushes never should be decontaminated. When a toothbrush becomes contaminated through contact with another brush or use by another child, it should be discarded and replaced with a new one.

Tooth brushing always should be supervised to ensure that toothbrushes are not shared and that they are handled properly.

Other

A dental dam and high volume evacuation may be used during dental procedures, when indicated, to minimize the amount of potentially contaminated splash and spatter, and to minimize direct contact with patients' oral mucosa.

Ventilation devices such as a one-way CPR airway (e.g., a pocket mask with a one-way valve) or oxygen with bagging capability must be available for those qualified to provide such care.

Eating, drinking, smoking: Do not eat, drink, smoke, apply cosmetics or lip balm, handle contact lenses or store food or drink in areas of possible exposure to (or storage of) blood, saliva, tissue or other potentially infectious materials. This would include the dental operatory, dental laboratory, sterilization area and darkroom/X-ray processing area.

Decontamination of equipment for servicing or maintenance: Contaminated equipment or instruments that are to be repaired on site or shipped for service are first to be cleaned and sterilized or disinfected. If a portion of the equipment cannot be cleaned and sterilized or disinfected, that portion should be identified with a biohazard label and an explanation to those who may handle the contaminated item. Utility gloves, masks and protective eyewear must be worn when routine maintenance is performed on equipment such as replacing filters on suction pumps, etc. Infection control practices/procedures should be communicated to the repair personnel.

Radiographic asepsis: Wear gloves while exposing films in the patient's mouth. Place exposed films in a paper cup. When all films are exposed, remove and discard gloves. Reglove and transport to the darkroom, carefully open the packs and drop the films on a clean surface. Discard the contaminated wrappers, remove and discard the gloves, and process the films.

Daylight loader: When using an X-ray processor with a daylight loader, extra precautions are required to avoid contamination of the sleeves, and external and internal components of the processor. Place films in a paper cup as they are exposed. When all the films have been taken, remove gloves and place the paper cup containing exposed film packets into the daylight loader. Wearing clean gloves, insert hands through the sleeves of daylight loader. Open all film packets, allowing films to drop onto a clean surface. Do not touch films with gloved hands. Once all the film packets have been opened, discard empty film wrappers, remove gloves and process films with bare hands. For disposal, empty film packets and used gloves may be placed in the paper cup that was originally used to transport films into the daylight loader. If the insides of the insertion sleeves have ever been contaminated, double gloving may be used for protection when removing hands from the daylight loader. One pair of gloves should be removed after opening film packets, leaving a clean pair of gloves for handling films and touching the sleeves of the daylight loader.

Barrier pack films: X-ray films packaged in fluid impervious barriers are available. A slight modification of the recommended X-ray and darkroom protocol is indicated. After exposing the film, pull on the edges of the barrier pack, allowing the film to drop into a clean paper cup without contaminating the inner film packet. When all films have been exposed and collected in the cup, remove procedure gloves and take films to the darkroom or daylight loader for processing.

Implementation of Recommended Infection-Control Practices for Dentistry

Emphasis should be placed on consistent adherence to recommended infection-control strategies, including the use of protective barriers and appropriate methods of sterilizing or disinfecting instruments and environmental surfaces. Each dental facility should develop a written protocol for instrument reprocessing, operatory cleanup, and management of injuries (3). Training of all DHCWs in proper infection-control practices should begin in professional and vocational schools and be updated with continuing education.

Additional Needs in Dentistry

Additional information is needed for accurate assessment of factors that may increase the risk for transmission of bloodborne pathogens and other infectious agents in a dental setting. Studies should address the nature, frequency, and circumstances of occupational exposures. Such information may lead to the development and evaluation of improved designs for dental instruments, equipment, and personal protective devices. In addition, more efficient reprocessing techniques should be considered in the design of future dental instruments and equipment. Efforts to protect both patients and DHCWs should include improved surveillance, risk assessment, evaluation of measures to prevent exposure, and studies of postexposure prophylaxis. Such efforts may lead to development of safer and more effective medical devices, work practices, and personal protective equipment that are acceptable to DHCWs, are practical and economical, and do not adversely affect patient care (54,55 ).

Internet Resources

American Dental Association, Statement on dental unit waterlines, 1995, http://www.ada.org/prac/position/lines.html

Centers for Disease Control and Prevention. Recommended Infection-Control Practices for Dentistry, 1993; MMWR 42(RR-8) http://www.cdc.gov/epo/mmwr/preview/mmwrhtml/00021095.htm

Center for Biofilm Engineering, Montana State University. Interdisciplinary glossary, 1999, http://www.erc.montana.edu/Res-Lib99-SW/glossary/Gterms.html

Environmental Protection Agency, National Primary Drinking Water Regulations, 1999, http://www.epa.gov/OGWDW/wot/appa.html

Occupational Safety and Health Administration. OSHA Technical manual TED 1-0.15A, 1999, http://www.osha-slc.gov/dts/osta/otm/otm_toc.html

References

  1. CDC. Recommended infection-control practices for dentistry. MMWR 1986;35:237-42.
  2. CDC. Recommendations for prevention of HIV in health-care settings. MMWR 1987;36:(No. 2S).
  3. US Department of Health and Human Services. Infection control file: practical infection control in the dental office. Atlanta, GA/Rockville, MD:CDC/FDA, 1989. (Available through the US Government Printing Office, Washington, DC, or the National Technical Information Services, Springfield, VA.)
  4. Department of Labor, Occupational Safety and Health Administration. 29 CFR Part 1910.1030, occupational exposure to bloodborne pathogens; final rule. Federal Register 56(235):64004-182, 1991.
  5. CDC. Update: universal precautions for prevention of transmission of human immunodeficiency virus, hepatitis B virus, and other bloodborne pathogens in health-care settings. MMWR 1988;37:377-82,387-8.
  6. CDC. Guidelines for prevention of transmission of human immunodeficiency virus and hepatitis B virus to health-care and public-safety workers.MMWR 1989;38(suppl. No. S-6):1-37.
  7. CDC. Protection against viral hepatitis: recommendations of the Immunization Practices Advisory Committee (ACIP). MMWR 1990;39(No. RR-2).
  8. CDC. Hepatitis B virus: a comprehensive strategy for eliminating transmission in the United States through universal childhood vaccination. MMWR 1991;40(No. RR-13).
  9. Garner JS, Favero MS. Guideline for handwashing and hospital environmental control, 1985. Atlanta: CDC, 1985; publication no. 99-1117.
  10. Garner JS. Guideline for prevention of surgical wound infections, 1985. Atlanta: CDC, 1985; publication no. 99-2381.
  11. CDC. Guidelines for preventing the transmission of tuberculosis in health-care settings, with special focus on HIV-related issues. MMWR 1990;39(No. RR-17).
  12. CDC. Recommendations for preventing transmission of human immunodeficiency virus and hepatitis B virus during exposure-prone invasive procedures. MMWR 1991;40(No. RR-8).
  13. CDC. Update:investigations of patients who have been treated by HIV-infected health-care workers. MMWR 1992;41:344-6.
  14. Chamberland ME, Bell DM. HIV transmission from health care worker to patient: what is the risk? Ann Intern Med 1992;116:871-3.
  15. Siew C, Chang B, Gruninger SE, Verrusio AC, Neidle EA. Self-reported percutaneous injuries in dentists: implications for HBV, HIV transmission risk. J Am Dent Assoc 1992;123:37-44.
  16. Ahtone J, Goodman RA. Hepatitis B and dental personnel: transmission to patients and prevention issues. J Am Dent Assoc 1983;106:219-22.
  17.  
  18. Hadler SC, Sorley DL, Acree KH, et al. An outbreak of hepatitis B in a dental practice. Ann Intern Med 1981;5:133-8.
  19. CDC. Hepatitis B among dental patients Indiana. MMWR 1985;34:73-5.
  20. Levin ML, Maddrey WC, Wands JR, et al. Hepatitis B transmission by dentists. JAMA 1974;228:1139-40.
  21. Rimland D, Parkin WE, Miller GB, et al. Hepatitis B outbreak traced to an oral surgeon. N Engl J Med 1977;296:953-8.
  22. Goodwin D, Fannin SL, McCracken BB. An oral surgeon-related hepatitis B outbreak. Calif Morbid 1976;14.
  23. Reingold AL, Kane MA, Murphy EL, et al. Transmission of hepatitis B by an oral surgeon. J Infect Dis 1982;145:262-8.
  24. Goodman RA, Ahtone JL, Finton RJ. Hepatitis B transmission from dental personnel to patients: unfinished business. Ann Intern Med 1982;96:119.
  25. Shaw FE, Barrett CL, Hamm R, et al. Lethal outbreak of hepatitis B in a dental practice. JAMA 1986;255:3261-4.
  26. CDC. Outbreak of hepatitis B associated with an oral surgeon, New Hampshire. MMWR 1987;36:132-3.
  27. Ciesielski C, Marianos D, Chin-Yih OU, et al. Transmission of human immunodeficiency virus in a dental practice. Ann Intern Med 1992;116:798-805.
  28. CDC. Investigations of patients who have been treated by HIV-infected health-care workers_ United States. MMWR 1993;42:329- 31, 337.
  29. Gooch B, Marianos D, Ciesielski C, et al. Lack of evidence for patient-to-patient transmission of HIV in a dental practice. J Am Dent Assoc 1993;124:38-44.
  30. Canter J, Mackey K, Good LS, et al. An outbreak of hepatitis B associated with jet injections in a weight reduction clinic. Arch Intern Med 1990;150:1923-7.
  31. Kent GP, Brondum J, Keenlyside RA, LaFazia LM, Scott HD. A large outbreak of acupuncture-associated hepatitis B. Am J Epidemiol 1988;127:591-8. 
  32. Polish LB, Shapiro CN, Bauer F, et al. Nosocomial transmission of hepatitis B virus associated with the use of a spring-loaded finger-stick device. N Engl J Med 1992;326:721-5.
  33. Siew C, Gruninger SE, Mitchell EW, Burrell KH. Survey of hepatitis B exposure and vaccination in volunteer dentists. J Am Dent Assoc 1987;114:457-9.
  34. CDC. Immunization recommendations for health-care-workers. Atlanta, GA: CDC, Division of Immunization, Center for Prevention Services, 1989.
  35. Petersen NJ, Bond WW, Favero MS. Air sampling for hepatitis B surface antigen in a dental operatory. J Am Dent Assoc 1979;99:465- 7.
  36. Bond WW, Petersen NJ, Favero MS, Ebert JW, Maynard JE. Transmission of type B viral hepatitis B via eye inoculation of a chimpanzee. J Clin Microbiol 1982;15:533-4.
  37. CDC. Public Health Service statement on management of occupational exposure to human immunodeficiency virus, including considerations regarding zidovudine postexposure use. MMWR 1990;39(No. RR-1).
  38. Miller CH, Palenik CJ. Sterilization, disinfection, and asepsis in dentistry. In: Block SS, ed. Disinfection, sterilization, and preservation, 4th ed. Philadelphia: Lea & Febiger, 1991:676-95.
  39. Favero MS, Bond WW. Chemical disinfection of medical and surgical materials. In: Block SS, ed. Disinfection, sterilization, and preservation, 4th ed. Philadelphia: Lea & Febiger, 1991:617-41.
  40. FDA, Office of Device Evaluation, Division of General and Restorative Devices, Infection Control Devices Branch. Guidance on the content and format of premarket notification {510 (k)} submissions for liquid chemical germicides. Rockville, MD: FDA, January 31, 1992:49.
  41. Rutala WA. APIC guideline for selection and use of disinfectants. Am J Infect Control 1990;18:99-117.
  42. Proposed American National Standard/American Dental Association Specification No. 59 for portable steam sterilizers for use in dentistry. Chicago: ADA, April 1991.
  43. CDC. Recommendations for preventing transmission of infection with human T-lymphotropic virus type III/lymphadenopathy-associated virus in the workplace. MMWR 1985;34:682-6,691-5.
  44. Council on Dental Materials, Instruments, and Equipment; Dental Practice; and Dental Therapeutics. American Dental Association. Infection control recommendations for the dental office and the dental laboratory. J Am Dent Assoc 1988;1126:241-8.
  45. Lewis DL, Boe RK. Cross infection risks associated with current procedures for using high-speed dental handpieces. J Clin Microbiol 1992;30:401-6.
  46. Crawford JJ, Broderius RK. Control of cross infection risks in the dental operatory: prevention of water retraction by bur cooling spray systems. J Am Dent Assoc 1988;116:685-7.
  47. Lewis DL, Arens M, Appleton SS, et al. Cross-contamination potential with dental equipment. Lancet 1992;340:1252-4.
  48. Bagga BSR, Murphy RA, Anderson AW, Punwani I. Contamination of dental unit cooling water with oral microorganisms and its prevention. J Am Dent Assoc 1984;109:712-6.
  49. Scheid RC, Kim CK, Bright JS, Whitely MS, Rosen S. Reduction of microbes in handpieces by flushing before use. J Am Dent Assoc 1982;105:658-60.
  50. Garner JS, Simmons BP. CDC guideline for isolation precautions in hospitals. Atlanta, GA: CDC, 1983; HHS publication no. (CDC)83-8314.
  51. Tate WH, White RR. Disinfection of human teeth for educational purposes. J Dent Educ 1991;55:583-5.
  52. Favero MS, Bond WW. Sterilization, disinfection, and antisepsis in the hospital. In: Balows A, Hausler WJ, Herrmann KL, Isenberg HD, Shadomy HJ, eds.Manual of clinical microbiology, 5th ed. Washington, DC: American Society for Microbiology, 1991:183-200.
  53. The Michigan Medical Waste Regulatory Act of 1990, Act No. 368 of the Public Health Acts of 1978, Part 138, Medical Waste, Section 13807 Definitions.
  54. Oregon Health Division. Infectious waste disposal; questions and answers pertaining to the Administrative Rules 333-18-040 through 333-18-070. Portland, OR: Oregon Health Division, 1989.
  55. Bell DM. Human immunodeficiency virus transmission in health care settings: risk and risk reduction. Am J Med 1991;91(suppl. 3B):294-300.
  56. Bell DM, Shapiro CN, Gooch BF. Preventing HIV transmission to patients during invasive procedures: the CDC perspective. J Public Health Dent (in press).
 
Centers for Disease Control and Prevention.
Recommended infection-control practices for dentistry, 1993. MWWR 1993; 42 (No. RR-8)
Organizations for Safety & Aepsis Procedures (OSAP)
 
 

Bloodborne Disease Transmission


- Gloving, Gowning, Masking, and Other Protective Barriers as Part of Universal Precautions
- Written Guidelines: Universal Precautions
General Information for Patients
Universal Precautions for Prevention of Transmission of HIV and Other Bloodborne Infections
Bloodborne Disease Transmission
HIV Transmission Risk in Dental Offices Practically Undetectable Barrier Precautions

- Gloves
- Eyewear
- Gowns

 Needlestick Precautions  Disinfection 

- Sterilization Practices

Chemical Germicides/ FDA and EPA Classifications Handpieces
Disposal of Sharp Instruments and Infectious Waste

- Disposal of Solid or Liquid Waste

Use of Extracted Teeth in Dental Educational Settings
Environmental Consideration for HIV Infection

- Sterilization and Disinfection
- Housekeeping
- Cleaning and Decontaminating Spills of Blood or Other Body Fluids
- Laundry
- Infective Waste
- Recommendations

Management of Exposures

General Information for Patients

Cleanliness and proper sterilization techniques have been a part of dental practices for many years, but recently a number of disease causing organisms such as HIV/AIDS, hepatitis B and C, and herpes viruses have made these techniques even more important.

Dental professionals are concerned about the possibility of disease transmission and are making several visible changes in the way dental services are provided. For example,

  1. More dentists are using the proper infection control procedures for all patients.
  2. Dentists, hygienists, and assistants are routinely wearing surgical gloves, protective eye wear, and masks during treatment of patients. The use of these barriers, greatly reduces the risk of transmission of microorganisms between patients and health-care workers.
  3. More dental personnel are receiving vaccination against the hepatitis B virus.
  4. Dentists are becoming more educated about the best methods to protect their patients

These safeguards will benefit everyone — patients, families, and dental personnel.

These infection control techniques are not costly and are of great value, considering the amount of protection that is provided. Many of these techniques have been practiced in the dental office for years.

The use of these infection control techniques and practices is strongly supported by organizations such as the Centers for Disease Control and Prevention, the American Dental Association, state boards of health, schools of dentistry, and many other health agencies and professional associations.

You can help your dental health professional by reporting any changes in your health status at each dental visit. Doing so will help your dental health professional provide the best treatment based on your health needs. And if you wish to know more about infection control issues, your dentist should be able to provide you with additional information.

Universal Precautions for Prevention of Transmission of HIV and Other Bloodborne Infections

"Universal precautions," as defined by CDC, are a set of precautions designed to prevent transmission of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and other bloodborne pathogens when providing first aid or health care. Under universal precautions, blood and certain body fluids of all patients are considered potentially infectious for HIV, HBV and other bloodborne pathogens.

Universal precautions apply to blood, other body fluids containing visible blood, semen, and vaginal secretions. Universal precautions also apply to tissues and to the following fluids: cerebrospinal, synovial, pleural, peritoneal, pericardial, and amniotic fluids. Universal precautions do not apply to feces, nasal secretions, sputum, sweat, tears, urine, and vomitus unless they contain visible blood. Universal precautions do not apply to saliva except when visibly contaminated with blood or in the dental setting where blood contamination of saliva is predictable.

Universal precautions involve the use of protective barriers such as gloves, gowns, aprons, masks, or protective eyewear, which can reduce the risk of exposure of the health care worker's skin or mucous membranes to potentially infective materials. In addition, under universal precautions, it is recommended that all health care workers take precautions to prevent injuries caused by needles, scalpels, and other sharp instruments or devices.

Pregnant health care workers are not known to be at greater risk of contracting HIV infection than are health care workers who are not pregnant; however, if a health care worker develops HIV infection during pregnancy, the infant is at risk of infection resulting from perinatal transmission. Because of this risk, pregnant health care workers should be especially familiar with, and strictly adhere to, precautions to minimize the risk of HIV transmission.

Gloving, Gowning, Masking, and Other Protective Barriers as Part of Universal Precautions

All health care workers should routinely use appropriate barrier precautions to prevent skin and mucous membrane exposure during contact with any patient's blood or body fluids that require universal precautions.

Gloves should be worn:

  1.  for touching blood and body fluids requiring universal precautions, mucous membranes, or nonintact skin of all patients, and
  2.  for handling items or surfaces soiled with blood or body fluids to which universal precautions apply.

Gloves should be changed after contact with each patient. Hands and other skin surfaces should be washed immediately or as soon as patient safety permits if contaminated with blood or body fluids requiring universal precautions. Hands should be washed immediately after gloves are removed.

Masks and protective eyewear or face shields should be worn by health care workers to prevent exposure of mucous membranes of the mouth, nose, and eyes during procedures that are likely to generate droplets of blood or body fluids requiring universal precautions. Gowns or aprons should be worn during procedures that are likely to generate splashes of blood or body fluids requiring universal precautions.

All health care workers should take precautions to prevent injuries caused by needles, scalpels, and other sharp instruments or devices during procedures; when cleaning used instruments; during disposal of used needles; and when handling sharp instruments after procedures. To prevent needlestick injuries, needles should not be recapped by hand, purposely bent or broken by hand, removed from disposable syringes, or otherwise manipulated by hand. After they are used, disposable syringes and needles, scalpel blades, and other sharp items should be placed in puncture-resistant containers for disposal. The puncture-resistant containers should be located as close as practical to the use area. All reusable needles should be placed in a puncture-resistant container for transport to the reprocessing area.

General infection control practices should further minimize the already minute risk for salivary transmission of HIV. These infection control practices include the use of gloves for digital examination of mucous membranes and endotracheal suctioning, handwashing after exposure to saliva, and minimizing the need for emergency mouth-to-mouth resuscitation by making mouthpieces and other ventilation devices available for use in areas where the need for resuscitation is predictable.

Written Guidelines: Universal Precautions

Universal precautions are discussed in the following documents:

  1. CDC. Recommendations for prevention of HIV transmission in health-care settings. MMWR 1987;36(suppl no. 2S).
  2. CDC. Update: Universal precautions for prevention of transmission of human immunodeficiency virus, hepatitis B virus, and other bloodborne pathogens in health-care settings. MMWR 1988;37:377-388.
  3. CDC. Guidelines for prevention of transmission of human immunodeficiency virus and hepatitis B virus to health-care and public-safety workers. MMWR 1989;38(S-6):1-36.

These three documents may be obtained by calling the AIDS Hotline at 1-800-342-2437 or the National AIDS Information Clearinghouse at 1-800-458-5231.

In addition, the Occupational Safety and Health Administration (OSHA) has published a standard on "bloodborne pathogens." For information about this document, call 202-219-7157.

For information on infection control in dental practice, call 1-800-458-5231 to obtain "The Infection Control File." For further questions on dental practice, call the Division of Oral Health, CDC, telephone 770-488-3034.

Bloodborne Disease Transmission

Hepatitis B (HBV) and C viruses (HCV) and HIV are important bloodborne diseases. Although the potential for HBV transmission in the workplace setting is greater than for HCV or HIV, the modes of transmission for these three viruses are similar. All have been transmitted in occupational settings. Blood is the single most important source of these viruses in the workplace setting. Protective measures against the transmission of HIV, HBV and HCV for dental workers should focus primarily on preventing exposures to blood as well as receiving the HBV vaccination.

The risk of hepatitis B infection following a parenteral (i.e., needlestick or cut) exposure to blood is directly proportional to the probability that the blood contains hepatitis B surface antigen, the immunity status of the recipient, and the efficiency of transmission. The probability of the source of the blood being positive for hepatitis B varies from l to 3 per thousand in the general population to 5% - 15% in groups at high risk for HBV infection, such as:

  1. Immigrants from areas of high endemicity (China and Southeast Asia, sub-Saharan Africa, most Pacific islands, and the Amazon Basin);
  2. Clients in institutions for the mentally retarded;
  3. Intravenous drug users; homosexually active males;
  4. Household (sexual and nonsexual) contacts of HBV carriers.

Of persons who have not had prior hepatitis B vaccination or post-exposure prophylaxis, 6% - 30% of persons who receive a needlestick exposure from an individual who is hepatitis B-positive will become infected.

The risk of infection with HCV following one needlestick exposure to blood from a patient known to be infected with HCV is approximately 3-10%; for HIV, the risk is even lower at 0.3%. This rate of transmission is considerably lower than that for HBV, probably as a result of the significantly lower concentrations of virus in the blood of HIV-infected persons.

An effective hepatitis B vaccine has been developed and is recommended for any health care provider, including all dental personnel. Also, hepatitis B immune globulin is available as a treatment in postexposure situations. However, the most important way to prevent bloodborne disease transmission is through safe handling of sharp instruments, use of barrier protection, and following disinfection and sterilization practices.

HIV Transmission Risk in Dental Offices Practically Undetectable

In the 20 years since the onset of HIV in the United States, studies continue to demonstrate that the risk of HIV transmission in dental offices is so low as to be almost undetectable, states a report by the American Dental Association (ADA). This ongoing research continues to support the dental office as a safe place to provide and receive oral health care when proper infection control procedures are followed.

According to the most recent Centers for Disease Control and Prevention statistics, as of December 1999:

  1. there is no documented evidence of patient-to-patient HIV transmission in the dental office;
  2. other than the Acer case, studies of HIV-infected dental workers have not identified a single instance of HIV transmission from an infected dental worker to a patient, and;
  3.  of 136 cases of health care workers with possible occupationally acquired HIV infection, six were associated with dental health care workers. Their positions within the dental office were not reported.

According to the ADA, billions of dental procedures have been performed safely. The rigorous infection control measures and universal precautions dentists take help protect patients from all bloodborne diseases, including AIDS.

Barrier Precautions

The following information summarizes the use of gloves, masks, protective eyewear, gowns, and the protection of equipment that is hard to disinfect.

  1. During dental procedures, dental health care workers must wear gloves when they put their hands into any patient's mouth, and change these gloves between patients. They should also wear gloves when they touch instruments, equipment, or surfaces that may be contaminated with blood or saliva.
  2. Hands must be washed and regloved before performing procedures on another patient. Repeated use of a single pair of gloves or washing of gloves between patients is not recommended, since such practice is likely to produce defects in the glove material, which will diminish its value as an effective barrier.
  3. Surgical masks and protective eyewear or chin-length plastic face shields must be worn when splashing or spattering of blood, saliva, or oral secretions is likely, as is common during dental procedures.
  4. Reusable or disposable gowns, laboratory coats, or uniforms must be worn when clothing is likely to be soiled with blood, saliva, or oral secretions. If reusable gowns are worn, they should be washed, using a normal laundry cycle. Gowns should be changed at least daily or when visibly soiled with blood.
  5. Disposable waterproof coverings such as impervious-backed paper, aluminum foil, or clear plastic wrap may be used to wrap hard-to-clean surfaces such as light handles or x-ray unit heads, etc. These surfaces may be contaminated by blood or saliva and are difficult or impossible to clean and disinfect. To replace the covering between patients, the coverings should be removed with gloved hands and discarded. Then, after removing the soiled gloves, the coverings can be replaced with clean material.

 Gloves

You are most likely to contact blood with your hands. If the skin of your hands is intact, it provides good protection from microorganisms that may be in blood. Frequently, however, there may be small unapparent breaks in the skin on your hands.

Wearing gloves will provide an extra barrier against the entry of microorganisms through any breaks in your skin.

Wear gloves whenever you put your hands into any patient's mouth or touch instruments, equipment, or surfaces that may be contaminated with blood. Use a new pair of gloves for every patient.

Three types of gloves are commonly available:

  1. Disposable examination gloves made of either vinyl or latex for procedures involving contact with oral mucous membranes.
  2. Sterile disposable gloves for use when sterility is necessary, such as during surgical procedures.
  3. General purpose utility gloves for use when cleaning instruments, equipment, and contaminated surfaces. Rubber household gloves are suitable, and can be decontaminated and reused.

Never reuse surgical or examination gloves. Washing these gloves may damage them and actually cause "wicking," which increases the flow of liquid through undetected holes in the gloves.

Utility gloves may be reused if they are not punctured or torn. They should be properly decontaminated before reuse.

If your gloves are torn, cut, or punctured, remove then immediately and dispose of them properly. Then wash your hands thoroughly with soap and water and put on a new pair of gloves.

As a barrier, there is no difference between an intact vinyl glove and an intact latex glove. However, any type of glove may be defective. It would be prudent, therefore, to make sure your gloves are intact before using them.

As a public health measure, it is not necessary to double-glove, as long as the glove is intact.

Eyewear

Wear either a mask and protective glasses or goggles, or a chin-length face shield that protects your eyes, nose, and mouth from spatter. Wear facial protection whenever blood or oral fluids contaminated by blood may be spattered, for example during patient treatment, while cleaning instruments, or when disposing of contaminated fluids.

Use a new surgical mask for every patient. If the mask becomes wet during the single treatment of a patient, the mask should be replaced.

Wash nondisposable facial protective equipment with detergent and water between patients and disinfect it with a tuberculocidal "hospital disinfectant" that is registered with the Environmental Protection Agency (EPA).

Gowns

Protect your street clothes from contamination by covering them with a gown or coat or wearing a uniform. The sleeve length of these work clothes may be long, medium, or short. Long sleeves will provide the most protection, but may become soiled and need to be changed more often during the course of the work day. If medium or short sleeves are used, be sure to wash your arms up to the sleeve length, while washing your hands before gloving.

Change these work clothes at least daily, or more often if soiled, especially if they become visibly contaminated with blood.

Work clothes soiled by blood, saliva, or oral secretions should be placed and transported in bags that prevent leakage. Wash soiled linens in hot or cold water with detergent and, if possible, chlorine bleach. Normal washing and drying cycles will remove or kill potentially harmful micro-organisms, including viruses. Be sure to follow the instructions of the detergent and machine manufacturers.

Needlestick Precautions

You, as a health-care workers, should take precautions to prevent injuries caused by needles and other sharp instruments. You should adhere to the following precautions during all procedures in which you may handle sharp instruments, including clean-up and disposal of used needles and other disposable sharp items.

  1. A disposable syringe with a disposable needle:

    A disposable syringe with a disposable needle is designed for single use only. The disposable needle should never be separated from its disposable syringe. Once used, this type of syringe and needle should be disposed of promptly and properly.

  2. A nondisposable aspirating syringe with a disposable needle: 

    When giving multiple injections on a patient with a single needle, either place the unsheathed needle out of your way in a safe, clean area where it cannot be contaminated, or use a one-handed recapping technique between injections.

  3. A nondisposable syringe with a nondisposable needle:

    A nondisposable syringe with a nondisposable needle should not be used for administering local anesthesia in the dental office.

Disinfection and Sterilization Practices

Cleaning, disinfection, and sterilization are all decontamination processes. These processes differ in the number and types of microorganisms killed. By knowing the differences between these processes, your will know how to choose the right way to reprocess reusable instruments and equipment.

Cleaning is the basic first step for all decontamination. When you clean, you physically remove debris and reduce the number of microorganisms present. You always need to clean before you disinfect or sterilize.

Disinfection is a process that kills disease-causing microorganisms, but not necessarily all microorganisms. There are three levels of disinfection: low, intermediate, and high.

  1. Low-level disinfection is the least effective disinfection process. It does not kill bacterial spores or Mycobacterium tuberculosis var. bovis, a laboratory test microorganism that is used to classify the strength of disinfectant chemicals.
  2. Intermediate-level disinfection is a disinfection process that does kill M. tuberculosis var. bovis, but not bacterial spores. If you use a process that kills M. tuberculosis var. bovis, you will also kill organisms that are easier to kill, such as the ones that cause hepatitis B and AIDS.
  3. High-level disinfection is a disinfection process that kills some, but not necessarily all, bacterial spores. This powerful process will also kill M. tuberculosis var. bovis, as well as other bacteria, fungi, and viruses.

Sterilization is a process that kills all microbial life, including bacterial spores, which are the most difficult form of microorganism to kill.

The choice of how to decontaminate anything should be based on how it will be used.

Instruments that will touch bone or penetrate tissue are called critical. Forceps, scalpels, and scalers are examples of critical items. Sterilize these critical instruments. Heat sterilization methods are preferable.

Instruments that will touch mucous membranes but will not touch bone or penetrate tissue are called semicritical. Mirrors and amalgam condensers are examples of semicritical items. Sterilize these semicritical instruments in an autoclave if they will not be damaged by heat. If they will be damaged by heat, use high-level disinfection.

Equipment and environmental surfaces that will come into contact only with intact skin are called noncritical. For noncritical equipment and surfaces that will touch only intact skin, use intermediate or low-level disinfection.

There may be ways to avoid having to decontaminate items with irregular surfaces that cannot be cleaned and disinfected easily. Some, such as saliva ejectors, are available in a disposable form and can be thrown away after a single use. Others, such as light handles and hand-operated chair controls, can be covered to avoid contamination altogether. Still others, however, such as light-curing wands, are not disposable and cannot be covered. Your dental supplier and the manufacturer of a particular piece of equipment or material are the best sources of information for decontaminating these items.

How to Sterilize

To sterilize, do the following:

  1. Cleaning is the first step in sterilization. Always wear heavy-duty (reusable utility type) gloves to lessen the risk of hand injuries. Do not use disposable examination gloves during cleaning. Before sterilization or high-level disinfection, instruments must be thoroughly cleaned to remove debris. Placing instruments into a container of water or disinfectant/detergent as soon as possible after use will prevent drying of patient materials and make cleaning easier and more efficient. Cleaning may be accomplished by thorough scrubbing with soap and water or a detergent solution, or by using a mechanical device (e.g., an ultrasonic cleaner). The use of covered ultrasonic cleaners, where possible, is recommended to increase efficiency of cleaning and to reduce handling of sharp instruments. All critical and semicritical dental instruments that are heat-stable must be routinely heat sterilized between uses. Be sure to follow the instructions of the manufacturers of the instruments and the sterilizers.
  2. Sterilize by using one of the following methods:
  3. Steam under pressure (steam autoclave)
    Dry heat
    Chemical under pressure (chemical autoclave)

Critical and semicritical instruments that are not going to be used immediately should be packaged prior to sterilization. The adequacy of sterilization cycles should be verified by the periodic use (e.g., at least weekly) of biologic indicators. Heat-sensitive chemical indicators (e.g., those that change color after exposure to heat) do not assure efficacy of a sterilization cycle but may be used on the outside of each pack to identify packs that have been processed through the heating cycle, or on the inside and center of instrument packs to assure heat penetration. These procedures are recommended for all dental practices.

The instructions of the manufacturers of medical/dental instruments and sterilization devices must be closely followed.

Sterilizing methods which use heat are preferred. However, there is a fourth sterilization method using a liquid "disinfectant/sterilant" that has been registered by the Environment Protection Agency (EPA) and also cleared for marketing by the Food and Drug Administration (FDA) for use on medical and dental instruments. This method is sometimes referred to as "cold sterilization". This procedure:

  1.  Requires that the dental instruments be immersed up to 10 hours in the chemical agent;
  2.  Cannot be verified by biologic monitors (i.e., spore tests);
  3.  Thus indications for use of liquid germicides to sterilize instruments are limited. If this method must be used for heat sensitive instruments, follow with aseptic rinsing (using sterile water), drying, and placement in a sterile container if the instrument is not used immediately.

To disinfect semicritical items that are damaged by heat, do the following:

  1. Clean by rinsing under a stream of water and scrubbing thoroughly with detergent and water. You can also use an ultrasonic cleaner. Rinse and dry the items completely. Remember that cleaning is the first step in decontamination.
  2. Sterilize items not damaged by heat and use high-level disinfection on other items. High-level disinfection can be carried out by soaking them in a liquid chemical germicide registered with the Environmental Protection Agency (EPA) as a "disinfectant/sterilant" and cleared by the FDA for use in sterilizing or disinfecting medical and dental instruments. Soak these items for the amount of time listed by the manufacturer.

Anything that will touch only intact skin is a noncritical item. Chairs and counter tops are examples of noncritical items. You can clean noncritical items using absorbent towels, water, and either soap or a disinfectant product registered by the Environmental Protection Agency (EPA) for cleaning. Scrubbing itself removes microorganisms very well, however, and is probably as important as the cleaning agent used.

If a noncritical item is contaminated, do the following:

  1. Remove any visible contamination with a paper towel or moist cloth.
  2. Clean the item well with detergent and water.
  3. If there is visible blood or bloody saliva, carry out intermediate-level disinfection using a liquid chemical germicide registered with the EPA as a tuberculocidal "hospital disinfectant," or a solution of bleach.

To disinfect with bleach, do the following:

  1. Mix a fresh solution daily, using household bleach and water. Either 1 part bleach to 100 parts water or 1/4 cup bleach in 1 gallon of water will provide a solution that is strong enough. Wipe the cleaned item with the bleach solution and allow to air dry.
Alcohol is not recommended for disinfecting contaminated environmental surfaces because it evaporates quickly and does not allow sufficient contact time for effective action. 

Chemical Germicides / FDA and EPA Classifications

The Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA) coregulate liquid chemical germicides.

Any chemical you use should have a label that shows the following:

  1. Either the FDA or EPA classification;
  2. EPA registration and establishment numbers;
  3. Directions for use and disposal.

The FDA is the principal regulator for chemicals used as "sterilants/disinfectants. "If "sterilant/disinfectant" and the word "sporicidal," (kills spores) are on the label, you can use the chemical for either sterilization or high-level disinfection. The same concentration of the chemical is used for both processes. Be sure to follow closely the instructions on the label regarding appropriate contact times, temperature, and concentration. Chemical germicides that are less potent than the "sterilant/disinfectant" category are not appropriate for reprocessing dental instruments that have contacted oral tissues.

The Environmental Protection Agency (EPA) is the principal regulator for chemicals used to disinfect contaminated environmental surfaces. These chemicals fall into two categories:

  1. For intermediate level disinfection, use EPA Classification: Hospital disinfectants with tuberculocidal activity label claims. Look for the terms "tuberculocidal" and "hospital disinfectant" on the label of any chemical you use for intermediate-level disinfection.
  2. For low-level disinfection, use EPA Classification: non-tuberculocidal hospital disinfectant.

If the label reads "hospital disinfectant", but does not indicate that it is tuberculocidal, then use this chemical for low-level disinfection. 

Environmental Considerations for HIV Infection

No environmentally mediated mode of HlV transmission has been documented. Nevertheless, the precautions described below should be taken routinely in the care of all patients.

Sterilization and Disinfection

Standard sterilization and disinfection procedures for patient care equipment currently recommended for use in a variety of health care settingsincluding hospitals, medical and dental clinics and offices, hemodialysis centers, emergency care facilities, and long-term nursing-care facilities—are adequate to sterilize or disinfect instruments, devices, or other items contaminated with blood or other body fluids from persons infected with blood-borne pathogens including HIV.

Instruments or devices that enter sterile tissue or the vascular system of any patient or through which blood flows should be sterilized before reuse. Devices or items that contact intact mucous membranes should be sterilized or receive high level disinfection, a procedure that kills vegetative organisms and viruses but not necessarily large numbers of bacterial spores. Chemical germicides that are registered with the U.S. Environmental Protection Agency (EPA) as "sterilants" may be used either for sterilization or for high level disinfection depending on contact time.

Medical devices or instruments that require sterilization or disinfection should be thoroughly cleaned before being exposed to the germicide, and the manufacturer's instructions for the use of the germicide should be followed. Further, it is important that the manufacturer's specifications for compatibility of the medical device with chemical germicides be closely followed. Information on specific label claims of commercial germicides can be obtained by writing to the Disinfectants Branch, Office of Pesticides, Environmental Protection Agency, 401 M Street, SW, Washington, D.C. 20460.

Studies have shown that HIV is inactivated rapidly after being exposed to commonly used chemical germicides at concentrations that are much lower than used in practice. Embalming fluids are similar to the types of chemical germicides that have been tested and found to completely inactivate HIV. In addition to commercially available chemical germicides, a solution of sodium hypochlorite (household bleach) prepared daily is an inexpensive and effective germicide. Concentrations ranging from approximately 500 ppm (1: 100 dilution of household bleach) sodium hypochlorite to 5000 ppm (1:10 dilution of household bleach) are effective depending on the amount of organic material (e.g., blood, mucus) present on the surface to be cleaned and or serum of patients with HIV infection. HIV was detectable by tissue-culture techniques 1-3 days after drying, but the rate of inactivation was rapid. Studies performed at CDC have also shown that drying HIV causes a rapid (within several hours) 1-2 log (90-99% ) reduction in HIV concentration. In tissue-culture fluid, cell-free HIV could be detected up to 15 days at room temperature, up to 11 days at 37 C (98.6 F), and up to 1 day if the HIV was cell-associated.

When considered in the context of environmental conditions in health-care facilities, these results do not require any changes in currently recommended sterilization, disinfection, or housekeeping strategies. When medical devices are contaminated with blood or other body fluids, existing recommendation include the cleaning of these instruments, followed by disinfection or sterilization, depending on the type of medical device. These protocols assume "worst-case" conditions of extreme virologic and microbiological contamination, and whether viruses have been inactivated after drying plays no role in formulating these strategies. Consequently, no changes in published procedures for cleaning, disinfecting, or sterilizing need to be made.

Housekeeping

Environmental surfaces such as wall, floors, and other surfaces are not associated with transmission of infections to patients or health-care workers. Therefore, extraordinary attempts to disinfect or sterilize these environmental surfaces are not necessary. However, cleaning and removal of soil should be done routinely.

Cleaning schedules and methods vary according to the area of the hospital or institution, type of surface to be cleaned, and the amount and type of soil present. Horizontal surfaces (e.g., bedside tables and hard-surfaced flooring) in patient-care areas are usually cleaned on a regular basis, when soiling or spills occur, and when a patient is discharged. Cleaning of walls, blinds, and curtains is recommended only if they are visibly soiled. Disinfectant fogging is an unsatisfactory method of decontaminating air and surfaces and is not recommended.

Disinfectant-detergent formulations registered by EPA can be used for cleaning environmental surfaces, but the actual physical removal of microorganism by scrubbing is probably at least as  important as any antimicrobial effect of the cleaning agent used. Therefore, cost, safety, and acceptability by housekeepers can be the main criteria for selecting any such registered agent. The manufacturers' instructions for appropriate use should be followed.

Cleaning and Decontaminating Spills of Blood or Other Body Fluids

Chemical germicides that are approved for use as "hospital disinfectants" and are tuberculocidal when used at recommended dilutions can be used to decontaminate spills of blood and other body fluids. Strategies for decontaminating spills of blood and other body fluids in a patient-care setting are different than for spills of cultures or other materials in clinical, public health, or research laboratories. In patient-care areas, visible material should first be removed and then the area should be decontaminated. With large spills of cultured or concentrated infectious agents in the laboratory, the contaminated area should be flooded with a liquid germicide before cleaning, then decontaminated with fresh germicidal chemical. In both settings, gloves should be worn during the cleaning and decontaminating procedures.

Laundry

Although soiled linen has been identified as a source of large numbers of certain pathogenic microorganisms, the risk of actual disease transmission is negligible. Rather than rigid procedures and specifications, hygienic and common-sense storage and processing of clean and soiled linen are recommended . Soiled linen should be handled as little as possible and with minimum agitation to prevent gross microbial contamination of the air and of persons handling the linen. All soiled linen should be bagged at the location where it was used; it should not be sorted or rinsed in patient-care areas. Linen soiled with blood or body fluids should be placed and transported in bags that prevent leakage. If hot water is used linen should be washed with detergent in water at least 71 C ( 160 F) for 25 minutes. If low-temperature (<70 C [158 F]) laundry cycles are used, chemicals suitable for low temperature washing at proper use concentration should be used.

Infective Waste

There is no epidemiologic evidence to suggest that most hospital waste is any more infective than residential waste. Moreover, there is no epidemiologic evidence that hospital waste has caused disease in the community as a result of improper disposal. Therefore, identifying wastes for which special precautions are indicated is largely a matter of judgment about the relative risk of disease transmission. The most practical approach to the management of infective waste is to identify those wastes with the potential for causing infection during handling and disposal and for which some special precautions appear prudent. Hospital wastes for which special precautions appear prudent include microbiology laboratory waste, pathology waste, and blood specimens or blood products. While any item that has had contact with blood, exudates, or secretions may be potentially infective, it is not usually considered practical or necessary to treat all such waste as infective. Infective waste, in general, should either be incinerated or should be autoclaved before disposal in a sanitary landfill. Bulk blood, suctioned fluids, excretions, and secretions may be carefully poured down a drain connected to a sanitary sewer. Sanitary sewers may also be used to dispose of other infectious wastes capable of being ground and flushed into the sewer.

Management of Exposures

An occupational exposure that may place a worker at risk of HIV or HBV infection is defined as follows:
Contact with blood, tissues, or other body fluids to which universal precautions apply, including laboratory specimens that contain HIV or HBV with:
  1. An injury to the skin (e.g., a needlestick or cut with a sharp object);
  2. Mucous membranes; or
  3. Skin (especially when the exposed skin is chapped, abraded, or afflicted with dermatitis, or the contact is prolonged or involves an extensive area).

After an occupational exposure, the source patient should be informed of the incident and tested for serologic evidence of HIV infection and hepatitis B surface antigen after consent is obtained.

Health-care workers who have received an occupational injury should contact their personal physician as soon as possible, or contact their local health department.

Further information on postexposure management is provided by CDCs Hospital Infections Program, National Center for Infectious Diseases. 

Source:     Centers for Disease Control and Prevention
                  Division of Oral Health

Management of Occupational Exposures to Bloodborne Pathogens

Practice recommendation Implementation checklist

Practice recommendations Implementation checklist

Establish a bloodborne pathogen policy. 

All institutions where health-care personnel (HCP) might experience exposures should have a written policy for management of exposures.

The policy should be based on the U.S. Public Health Service (PHS) guidelines.

The policy should be reviewed periodically to ensure that it is consistent with PHS recommendations.

Implement management policies. 

 

Health-care facilities (HCF) should provide appropriate training to all personnel on the prevention of and response to occupational exposures.

HCF should establish hepatitis B vaccination programs.

HCF should establish exposure-reporting systems.

HCF should have personnel who can manage an exposure readily available at all hours of the day.

HCF should have ready access to postexposure prophylaxis (PEP) for use by exposed personnel as necessary.

Establish laboratory capacity for ü HCF should provide prompt processing bloodborne pathogen testing. of exposed person and source person specimens to guide management of occupational exposures.

Testing should be performed with appropriate counseling and consent.

Select and use appropriate PEP regimens. 

 

 

HCF should develop a policy for the selection and use of PEP antiretroviral regimens for HIV exposures within their institution.

Hepatitis B vaccine and HBIG should be available for timely administration.

HCF should have access to resources with expertise in the selection and use of PEP.

Provide access to counseling for 

HCF should provide counseling for exposed HCP. HCP who might need help dealing with the emotional effect of an exposure.

HCF should provide medication adherence counseling to assist HCP in completing HIV PEP as necessary.

Monitor for adverse effects of PEP.

HCP taking antiretroviral PEP should be monitored periodically for adverse effects of PEP through baseline and testing (every 2 weeks) and clinical evaluation.

Monitor for seroconversion.

HCF should develop a system to encourage exposed HCP to return for follow-up testing.

Exposed HCP should be tested for HCV and HIV.

Monitor exposure management 

HCF should develop a system to programs. monitor reporting and management of occupational exposures to ensure timely and appropriate response. 

Evaluate
exposure reports for completeness and accuracy,
access to care (i.e., the time of exposure to the time of evaluation), and
laboratory result reporting time.
Review
completion rates of HBV vaccination and HIV PEP and
completion of exposure follow-up.

Source: Practice Recommendations for Health-Care Facilities Implementing the U.S. Public Health Service Guidelines for     Management of Occupational Exposures to Bloodborne Pathogens.
Centers for Disease Control.
June 29, 2001. 

Recommendations for Preventing Transmission of HIV and HBV to Patients During Exposure- Prone Invasive Procedures

This document has been developed by the Centers for Disease Control (CDC) to update recommendations for prevention of transmission of human immunodeficiency virus (HIV) and hepatitis B virus (HBV) in the health-care setting. Current data suggest that the risk for such transmission from a health-care worker (HCW) to a patient during an invasive procedure is small; a precise assessment of the risk is not yet available. This document contains recommendations to provide guidance for prevention of HIV and HBV transmission during those invasive procedures that are considered exposure-prone.

Introduction

Recommendations have been made by the Centers for Disease Control (CDC) for the prevention of transmission of the human immunodeficiency virus (HIV) and the hepatitis B virus (HBV) in health-care settings (1-6). These recommendations emphasize adherence to universal precautions that require that blood and other specified body fluids of all patients be handled as if they contain blood-borne pathogens (1,2).

Previous guidelines contained precautions to be used during invasive procedures and recommendations for the management of HIV- and HBV-infected health-care workers (HCWs) (1). These guidelines did not include specific recommendations on testing HCWs for HIV or HBV infection, and they did not provide guidance on which invasive procedures may represent increased risk to the patient.

An invasive procedure is defined as "surgical entry into tissues, cavities, or organs or repair of major traumatic injuries" associated with any of the following: "1) an operating or delivery room, emergency department, or outpatient setting, including both physicians' and dentists' offices; 2) cardiac catheterization and angiographic procedures; 3) a vaginal or cesarean delivery or other invasive obstetric procedure during which bleeding may occur; or 4) the manipulation, cutting, or removal of any oral or perioral tissues, including tooth structure, during which bleeding occurs or the potential for bleeding exists."

The recommendations outlined in this document are based on the following considerations:
Infected HCWs who adhere to universal precautions and who do not perform invasive procedures pose no risk for transmitting HIV or HBV to patients.
Infected HCWs who adhere to universal precautions and who perform certain exposure-prone procedures pose a small risk for transmitting HBV to patients.
HIV is transmitted much less readily than HBV. In the interim, until further data are available, additional precautions are prudent to prevent HIV and HBV transmission during procedures that have been linked to HCW-to-patient HBV transmission or that are considered exposure-prone.

Infection-Control Practices

Previous recommendations have specified that infection-control programs should incorporate principles of universal precautions (i.e., appropriate use of hand washing, protective barriers, and care in the use and disposal of needles and other sharp instruments) and should maintain these precautions rigorously in all health-care settings (1,2,5). Proper application of these principles will assist in minimizing the risk of transmission of HIV or HBV from patient to HCW, HCW to patient, or patient to patient.

As part of standard infection-control practice, instruments and other reusable equipment used in performing invasive procedures should be appropriately disinfected and sterilized as follows (7):
Equipment and devices that enter the patient's vascular system or other normally sterile areas of the body should be sterilized before being used for each patient.
Equipment and devices that touch intact mucous membranes but do not penetrate the patient's body surfaces should be sterilized when possible or undergo high-level disinfection if they cannot be sterilized before being used for each patient.
Equipment and devices that do not touch the patient or that only touch intact skin of the patient need only be cleaned with a detergent or as indicated by the manufacturer.

Compliance with universal precautions and recommendations for disinfection and sterilization of medical devices should be scrupulously monitored in all health-care settings (1, 7, 8). Training of HCWs in proper infection-control technique should begin in professional and vocational schools and continue as an ongoing process. Institutions should provide all HCWs with appropriate in service education regarding infection control and safety and should establish procedures for monitoring compliance with infection-control policies.

All HCWs who might be exposed to blood in an occupational setting should receive hepatitis B vaccine, preferably during their period of professional training and before any occupational exposures could occur (8, 9).

Transmission of HBV During Invasive Procedures

Since the introduction of serologic testing for HBV infection in the early 1970s, there have been published reports of 20 clusters in which a total of over 300 patients were infected with HBV in association with treatment by an HBV-infected HCW. In 12 of these clusters, the implicated HCW did not routinely wear gloves; several HCWs also had skin lesions that may have facilitated HBV transmission (10-22). These 12 clusters included nine linked to dentists or oral surgeons and one cluster each linked to a general practitioner, an inhalation therapist, and a cardiopulmonary-bypass-pump technician. The clusters associated with the inhalation therapist and the cardiopulmonary-bypass-pump technicianand some of the other 10 clusters2could possibly have been prevented if current recommendations on universal precautions, including glove use, had been in effect. In the remaining eight clusters, transmission occurred despite glove use by the HCWs; five clusters were linked to obstetricians or gynecologists, and three were linked to cardiovascular surgeons (6, 22-28). In addition, recent unpublished reports strongly suggest HBV transmission from three surgeons to patients in 1989 and 1990 during colorectal (CDC, unpublished data), abdominal, and cardiothoracic surgery (29).

Seven of the HCWs who were linked to published clusters in the United States were allowed to perform invasive procedures following modification of invasive techniques (e.g., double gloving and restriction of certain high-risk procedures) (6,11- 13,15,16, 24). For five HCWs, no further transmission to patients was observed. In two instances involving an obstetrician/gynecologist and an oral surgeon, HBV was transmitted to patients after techniques were modified (6, 12).

Review of the 20 published studies indicates that a combination of risk factors accounted for transmission of HBV from HCWs to patients. Of the HCWs whose hepatitis B e antigen (HBeAg) status was determined (17 of 20), all were HBeAg positive. The presence of HBeAg in serum is associated with higher levels of circulating virus and therefore with greater infectivity of hepatitis-B-surface-antigen (HBsAg)-positive individuals; the risk of HBV transmission to an HCW after a percutaneous exposure to HBeAg-positive blood is approximately 30% (30-32). In addition, each report indicated that the potential existed for contamination of surgical wounds or traumatized tissue, either from a major break in standard infection-control practices (e.g., not wearing gloves during invasive procedures) or from unintentional injury to the infected HCW during invasive procedures (e.g., needle sticks incurred while manipulating needles without being able to see them during suturing).

Most reported clusters in the United States occurred before awareness increased of the risks of transmission of blood-borne pathogens in health-care settings and before emphasis was placed on the use of universal precautions and hepatitis B vaccine among HCWs. The limited number of reports of HBV transmission from HCWs to patients in recent years may reflect the adoption of universal precautions and increased use of HBV vaccine. However, the limited number of recent reports does not preclude the occurrence of undetected or unreported small clusters or individual instances of transmission; routine use of gloves does not prevent most injuries caused by sharp instruments and does not eliminate the potential for exposure of a patient to an HCW's blood and transmission of HBV (6, 22-29).

Hepatitis B Immunization

HBV Infection is the major infectious occupational hazard for health care and public safety workers. The risk of acquiring HBV Infection from occupational exposures is dependent on the frequency of percutaneous and permucosal exposures to blood or blood products. Any health care or public safety worker may be at high risk for HBV exposure depending on the tasks that he or she performs. Workers performing tasks involving exposure to blood or blood-contaminated body fluids should be vaccinated.

Risks among health care professionals vary during the training and working career of each individual but are often highest during the professional training period. For this reason, vaccination should be completed during training in schools of medicine, dentistry, nursing, laboratory technology, and other allied health professions before trainees have their contact with blood.

  1. Persons at risk for hepatitis B virus infection who are demonstrated or judged likely to be susceptible should be vaccinated. Health-care workers who have contact with blood or blood products are at increased risk. These groups include (but are not limited to) physicians, nursing staff, dental professionals, and laboratory technicians.
  2. Before immunizing, serologic screening for hepatitis B need not be done unless the provider considers it cost-effective or the potential vaccine requests it.
  3. Prophylaxis with Hepatitis B immune globulin (passive immunization) and vaccine (active immunization) should be used when indicated, such as following needle-stick or percutaneous exposure to blood that is known to be at high risk for being HVsAG-positive. (See MMWR 1991;40:RR-13:15-17 for more details on post exposure prophylaxis.) Any needlestick exposure in an unvaccinated person should lead to initiation of the HB vaccine series.
  4. Immune globulins should not be used as a substitute when active immunization is indicated.

Transmission of HIV During Invasive Procedures

The risk of HIV transmission to an HCW after percutaneous exposure to HIV-infected blood is considerably lower than the risk of HBV transmission after percutaneous exposure to HBeAg-positive blood (0.3% versus approximately 30%) (33-35). Thus, the risk of transmission of HIV from an infected HCW to a patient during an invasive procedure is likely to be proportionately lower than the risk of HBV transmission from an HBeAg-positive HCW to a patient during the same procedure. As with HBV, the relative infectivity of HIV probably varies among individuals and over time for a single individual. Unlike HBV infection, however, there is currently no readily available laboratory test for increased HIV infectivity.

Investigation of a cluster of HIV infections among patients in the practice of one dentist with acquired immunodeficiency syndrome (AIDS) strongly suggested that HIV was transmitted to five of the approximately 850 patients evaluated through June 1991 (36-38). The investigation indicates that HIV transmission occurred during dental care, although the precise mechanisms of transmission have not been determined. In two other studies, when patients cared for by a general surgeon and a surgical resident who had AIDS were tested, all patients tested, 75 and 62, respectively, were negative for HIV infection (39, 40). In a fourth study, 143 patients who had been treated by a dental student with HIV infection and were later tested were all negative for HIV infection (41). In another investigation, HIV antibody testing was offered to all patients whose surgical procedures had been performed by a general surgeon within 7 years before the surgeon's diagnosis of AIDS; the date at which the surgeon became infected with HIV is unknown (42). Of 1,340 surgical patients contacted, 616 (46%) were tested for HIV. One patient, a known intravenous drug user, was HIV positive when tested but may already have been infected at the time of surgery. HIV test results for the 615 other surgical patients were negative (95% confidence interval for risk of transmission per operation=0.0%-0.5%).

The limited number of participants and the differences in procedures associated with these five investigations limit the ability to generalize from them and to define precisely the risk of HIV transmission from HIV-infected HCWs to patients. A precise estimate of the risk of HIV transmission from infected HCWs to patients can be determined only after careful evaluation of a substantially larger number of patients whose exposure-prone procedures have been performed by HIV-infected HCWs.

Exposure-Prone Procedures

Despite adherence to the principles of universal precautions, certain invasive surgical and dental procedures have been implicated in the transmission of HBV from infected HCWs to patients, and should be considered exposure-prone. Reported examples include certain oral, cardiothoracic, colorectal (CDC, unpublished data), and obstetric/gynecologic procedures (6, 12, 22-29).

Certain other invasive procedures should also be considered exposure-prone. In a prospective study CDC conducted in four hospitals, one or more percutaneous injuries occurred among surgical personnel during 96 (6.9%) of 1,382 operative procedures on the general surgery, gynecology, orthopedic, cardiac, and trauma services (43). Percutaneous exposure of the patient to the HCW's blood may have occurred when the sharp object causing the injury recontacted the patient's open wound in 28 (32%) of the 88 observed injuries to surgeons (range among surgical specialties=8%-57%; range among hospitals=24%-42%). Characteristics of exposure-prone procedures include digital palpation of a needle tip in a body cavity or the simultaneous presence of the HCW's fingers and a needle or other sharp instrument or object in a poorly visualized or highly confined anatomic site. Performance of exposure-prone procedures presents a recognized risk of percutaneous injury to the HCW, and if such an injury occurs the HCW's blood is likely to contact the patient's body cavity, subcutaneous tissues, and/or mucous membranes.

Experience with HBV indicates that invasive procedures that do not have the above characteristics would be expected to pose substantially lower risk, if any, of transmission of HIV and other blood-borne pathogens from an infected HCW to patients.

Recommendations

Investigations of HIV and HBV transmission from HCWs to patients indicate that, when HCWs adhere to recommended infection-control procedures, the risk of transmitting HBV from an infected HCW to a patient is small, and the risk of transmitting HIV is likely to be even smaller. However, the likelihood of exposure of the patient to an HCW's blood is greater for certain procedures designated as exposure-prone. To minimize the risk of HIV or HBV transmission, the following measures are recommended:

  1. All HCWs should adhere to universal precautions, including the appropriate use of hand washing, protective barriers, and care in the use and disposal of needles and other sharp instruments. HCWs who have exudative lesions or weeping dermatitis should refrain from all direct patient care and from handling patient-care equipment and devices used in performing invasive procedures until the condition resolves. HCWs should also comply with current guidelines for disinfection and sterilization of reusable devices used in invasive procedures.
  2. Currently available data provide no basis for recommendations to restrict the practice of HCWs infected with HIV or HBV who perform invasive procedures not identified as exposure-prone, provided the infected HCWs practice recommended surgical or dental technique and comply with universal precautions and current recommendations for sterilization/disinfection.
  3. Exposure-prone procedures should be identified by medical/surgical/dental organizations and institutions at which the procedures are performed.
  4. HCWs who perform exposure-prone procedures should know their HIV antibody status. HCWs who perform exposure-prone procedures and who do not have serologic evidence of immunity to HBV from vaccination or from previous infection should know their HBsAg status and, if that is positive, should also know their HBeAg status.
  5. HCWs who are infected with HIV or HBV (and are HBeAg positive) should not perform exposure-prone procedures unless they have sought counsel from an expert review panel and been advised under what circumstances, if any, they may continue to perform these procedures.* Such circumstances would include notifying prospective patients of the HCW's seropositivity before they undergo exposure-prone invasive procedures.
  6. Mandatory testing of HCWs for HIV antibody, HBsAg, or HBeAg is not recommended. The current assessment of the risk that infected HCWs will transmit HIV or HBV to patients during exposure-prone procedures does not support the diversion of resources that would be required to implement mandatory testing programs. Compliance by HCWs with recommendations can be increased through education, training, and appropriate confidentiality safeguards.

*The review panel should include experts who represent a balanced perspective. Such experts might include all of the following: a) the HCW's personal physician(s), b) an infectious disease specialist with expertise in the epidemiology of HIV and HBV transmission, c) a health professional with expertise in the procedures performed by the HCW, and d) state or local public health official(s). If the HCW's practice is institutionally based, the expert review panel might also include a member of the infection-control committee, preferably a hospital epidemiologist. HCWs who perform exposure-prone procedures outside the hospital/institutional setting should seek advice from appropriate state and local public health officials regarding the review process. Panels must recognize the importance of confidentiality and the privacy rights of infected HCWs.

HCWs Whose Practices Are Modified Because of HIV or HBV Status

HCWs whose practices are modified because of their HIV or HBV infection status should, whenever possible, be provided opportunities to continue appropriate patient-care activities. Career counseling and job retraining should be encouraged to promote the continued use of the HCW's talents, knowledge, and skills. HCWs whose practices are modified because of HBV infection should be reevaluated periodically to determine whether their HBeAg status changes due to resolution of infection or as a result of treatment (44).

Notification of Patients and Follow-Up Studies

The public health benefit of notification of patients who have had exposure-prone procedures performed by HCWs infected with HIV or positive for HBeAg should be considered on a case-by-case basis, taking into consideration an assessment of specific risks, confidentiality issues, and available resources. Carefully designed and implemented follow-up studies are necessary to determine more precisely the risk of transmission during such procedures. Decisions regarding notification and follow-up studies should be made in consultation with state and local public health officials.

References

  1. CDC. Recommendations for prevention of HIV transmission in health-care settings. MMWR 1987;36(suppl. no. 2S):1-18S.
  2. CDC. Update: Universal precautions for prevention of transmission of human immunodeficiency virus, hepatitis B virus, and other bloodborne pathogens in health-care settings. MMWR 1988;37:377-82,387-8.
  3. CDC. Hepatitis Surveillance Report No. 48. Atlanta: U.S. Department of Health and Human Services, Public Health Service, 1982:2-3.
  4. CDC. CDC Guideline for Infection Control in Hospital Personnel, Atlanta, Georgia: Public Health Service, 1983. 24 pages. (GPO# 6AR031488305).
  5. CDC. Guidelines for prevention of transmission of human immunodeficiency virus and hepatitis B virus to health-care and public-safety workers. MMWR 1989;38;(suppl. no. S-6):1-37.
  6. Lettau LA, Smith JD, Williams D, et al. Transmission of hepatitis B with resultant restriction of surgical practice. JAMA 1986;255:934-7.
  7. CDC. Guidelines for the prevention and control of nosocomial infections: guideline for handwashing and hospital environmental control. Atlanta, Georgia: Public Health Service, 1985. 20 pages. (GPO# 544-436/24441).
  8.  Department of Labor, Occupational Safety and Health Administration. Occupational exposure to bloodborne pathogens: proposed rule and notice of hearing. Federal Register 1989;54:23042-139.
  9. CDC. Protection against viral hepatitis: recommendations of the immunization practices advisory committee (ACIP). MMWR 1990;39:(no. RR-2).
  10. Levin ML, Maddrey WC, Wands JR, Mendeloff AI. Hepatitis B transmission by dentists. JAMA 1974; 228:1139-40.
  11. Rimland D, Parkin WE, Miller GB, Schrack WD. Hepatitis B outbreak traced to an oral surgeon. N Engl J Med 1977;296:953-8.
  12. Goodwin D, Fannin SL, McCracken BB. An oral-surgeon related hepatitis-B outbreak. California Morbidity 1976;14.
  13. Hadler SC, Sorley DL, Acree KH, et al. An outbreak of hepatitis B in a dental practice. Ann Intern Med 1981;95:133-8.
  14. Reingold AL, Kane MA, Murphy BL, Checko P, Francis DP, Maynard JE. Transmission of hepatitis B by an oral surgeon. J Infect Dis 1982;145:262-8.
  15. Goodman RA, Ahtone JL, Finton RJ. Hepatitis B transmission from dental personnel to patients: unfinished business (Editorial). Ann Intern Med 1982;96:119.
  16. Ahtone J, Goodman RA. Hepatitis B and dental personnel: transmission to patients and prevention issues. J Am Dent Assoc 1983;106:219-22.
  17. Shaw FE, Jr, Barrett CL, Hamm R, et al. Lethal outbreak of hepatitis B in a dental practice. JAMA 1986;255:3260-4.
  18. CDC. Outbreak of hepatitis B associated with an oral surgeon, New Hampshire. MMWR 1987;36:132-3.
  19. Grob PJ, Moeschlin P. Risk to contacts of a medical practitioner carrying HBsAg. (Letter). N Engl J Med 1975;293:197.
  20. Grob PJ, Bischof B, Naeff F. Cluster of hepatitis B transmitted by a physician. Lancet 1981;2:1218-20.
  21. Snydman DR, Hindman SH, Wineland MD, Bryan JA, Maynard JE. Nosocomial viral hepatitis B. A cluster among staff with subsequent transmission to patients. Ann Intern Med 1976;85:573-7.
  22. Coutinho RA, Albrecht-van Lent P, Stoutjesdijk L, et al. Hepatitis B from doctors (Letter). Lancet 1982;1:345-6.
  23. Anonymous. Acute hepatitis B associated with gynaecological surgery. Lancet 1980;1:1-6.
  24. Carl M, Blakey DL, Francis DP, Maynard JE. Interruption of hepatitis B transmission by modification of a gynaecologist's surgical technique. Lancet 1982;1:731-3.
  25. Anonymous. Acute hepatitis B following gynaecological surgery. J Hosp Infect 1987;9:34-8.
  26. Welch J, Webster M, Tilzey AJ, Noah ND, Banatvala JE. Hepatitis B infections after gynaecological surgery. Lancet 1989;1:205-7.
  27. Haeram JW, Siebke JC, Ulstrup J, Geiram D, Helle I. HBsAg transmission from a cardiac surgeon incubating hepatitis B resulting in chronic antigenemia in four patients. Acta Med Scand 1981;210:389-92.
  28. Flower AJE, Prentice M, Morgan G, et al. Hepatitis B infection following cardiothoracic surgery (Abstract). 1990 International Symposium on Viral Hepatitis and Liver Diseases, Houston. 1990;94.
  29. Heptonstall J. Outbreaks of hepatitis B virus infection associated with infected surgical staff in the United Kingdom. Communicable Disease Reports 1991 (in press).
  30. Alter HJ, Seef LB, Kaplan PM, et al. Type B hepatitis: the infectivity of blood positive for e antigen and DNA polymerase after accidental needlestick exposure. N Engl J Med 1976;295:909-13.
  31. Seeff LB, Wright EC, Zimmerman HJ, et al. Type B hepatitis after needlestick exposure: prevention with hepatitis B immunoglobulin: final report of the Veterans Administration Cooperative Study. Ann Intern Med 1978;88:285-93.
  32. Grady GF, Lee VA, Prince AM, et al. Hepatitis B immune globulin for accidental exposures among medical personnel: final report of a multicenter controlled trial. J Infect Dis 1978;138:625-38.
  33. Henderson DK, Fahey BJ, Willy M, et al. Risk for occupational transmission of human immunodeficiency virus type 1 (HIV-1) associated with clinical exposures: a prospective evaluation. Ann Intern Med 1990;113:740-6.
  34. Marcus R, CDC Cooperative Needlestick Study Group. Surveillance of health-care workers exposed to blood from patients infected with the human immunodeficiency virus. N Engl J Med 1988;319:1118-23.
  35. Gerberding JL, Bryant-LeBlanc CE, Nelson K, et al. Risk of transmitting the human immunodeficiency virus, cytomegalovirus, and hepatitis B virus to health-care workers exposed to patients with AIDS and AIDS-related conditions. J Infect Dis 1987;156:1-8.
  36. CDC. Possible transmission of human immunodeficiency virus to a patient during an invasive dental procedure. MMWR 1990;39:489-93.
  37. CDC. Update: transmission of HIV infection during an invasive dental procedure - Florida. MMWR 1991;40:21-27,33.
  38. CDC. Update: transmission of HIV infection during invasive dental procedures - Florida. MMWR 1991;40:377-81.
  39. Porter JD, Cruikshank JG, Gentle PH, Robinson RG, Gill ON. Management of patients treated by a surgeon with HIV infection. (Letter) Lancet 1990;335:113-4.
  40. Armstrong FP, Miner JC, Wolfe WH. Investigation of a health-care worker with symptomatic human immunodeficiency virus infection: an epidemiologic approach. Milit Med 1987;152:414-8.
  41. Comer RW, Myers DR, Steadman CD, Carter MJ, Rissing JP, Tedesco FJ. Management considerations for an HIV positive dental student. J Dent Educ 1991;55:187-91.
  42. Mishu B, Schaffner W, Horan JM, Wood LH, Hutcheson R, McNabb P. A surgeon with AIDS: lack of evidence of transmission to patients. JAMA 1990;264:467-70.
  43. Tokars J, Bell D, Marcus R, et al. Percutaneous injuries during surgical procedures (Abstract). VII International Conference on AIDS. Vol 2. Florence, Italy, June 16-21, 1991:83.
  44. Perrillo RP, Schiff ER, Davis GL, et al. A randomized, controlled trial of interferon alfa-2b alone and after prednisone withdrawal for the treatment of chronic hepatitis B. N Engl J Med 1990;323:295-301.

Instrument Processing

 

  1. Introduction
  2. Procedures for Instrument Processing
  3. Table 2: Heat Sterilization Methods
  4. References

Introduction

The goal of this position paper is to describe procedures for the processing of contaminated dental instruments from the point of retrieving the instruments from chairside to the presentation of sterile instruments at the point of reuse. This information should assist dental health care workers in making decisions about instrument processing procedures. A major consideration during development of this document was safety for those who process instruments. Other considerations included time efficiency of handling instruments, minimizing instrument damage, and staff training. This document is consistent with the recommended practices from the Association for the Advancement of Medical Instrumentation (AAMI) for managing instruments prior to processing through portable steam or dry heat sterilizers (see references). The enclosed Table presents general information on the physical conditions, advantages, precautions, and monitoring of sterilization processes.

Exclusions

This position paper does not address procedures for gross debridement of instruments at chairside or details of sterilization monitoring.

Procedures for Instrument Processing

Wear appropriate personal protective equipment (PPE) when processing contaminated instruments including utility gloves and, if there is a potential for splash and spatter, a mask, protective eyewear and a protective gown or apron.
Step 1 - Transport

Transport contaminated instruments to the processing area in a manner that minimizes the risk of exposure to persons and the environment.
Use a rigid, leak-proof container.
Use appropriate personal protective equipment.
Step 2 - Cleaning

Clean instruments with a hands-free, mechanical process such as an ultrasonic cleaner or instrument washer.

If instruments cannot be cleaned immediately, pre-soaking or maintaining them in a moist environment may improve the cleaning process.
Insure that instruments are rinsed thoroughly.
Visually inspect the instruments for residual debris and damage, and reclean or replace as appropriate.
Dry instruments before packaging.
Follow manufacturers' recommendations to lubricate and/or use rust inhibitors that are appropriate for the sterilization process as needed.
Step 3 - Packaging

In a cleaned, low-contamination environment, wrap/package instruments in materials that are appropriate for the sterilization process to be used.

Use of multiparameter indicators (integrators) may provide a higher standard of sterility assurance.

Loose instruments should be packaged so that they lay in a single layer, not wrapped up so tightly as to exclude exposure to the sterilizing agent.
Avoid excess packaging material by using appropriately sized (not over-sized) packaging materials.
Chemical indicators are placed next to the instruments inside the packages. If an indicator is not visible on the outside of the package, place an external process indicator on the package.
 To maintain integrity of the package, follow only manufacturers' recommendations for sealing the package; and do not use staples, pins, or paper clips to seal packages.
 The shelf life of wrapped instruments processed through a sterilizer is event-related. Thus, the shelf life of a package ends when the integrity of the package becomes compromised, e.g., torn, punctured or moistened.
 Packages are dated on the date processed using methods that do not compromise the integrity of the wrapping material.

-     Label information can be pencil-written on tape and then the tape is placed on the package.

-     Label information may be written on the outside of the sealed area of packages.

Do not mark on non-woven wrapping materials.
Do not use ink on paper packaging materials.
Step 4 - Sterilization

Sterilization is to be accomplished using a device that has been cleared by the U.S. Food & Drug Administration (FDA) as a sterilizer.
 Load the sterilizer according to manufacturers' instructions.
 Do not overload the sterilizer.
Place packages on their edge, in single layers, or on racks to increase circulation of the sterilizing agent around the instruments. 
 Use manufacturers' recommended cycle times for wrapped instruments.
 Operate the sterilizer according to manufacturers' instructions.
 Allow packages to dry before removing them from the sterilizer.
 Allow packages to cool before handling.
Step 5 - Storage

Store instruments in a clean, dry environment in a manner that maintains the integrity of the package. Rotate packages so that those with the oldest sterilization dates will be used first.

Enclosed cabinets will increase the assurance that sterility of the package is maintained.
Step 6 - Delivery

Deliver packages to point of use in a manner that maintains sterility of the instruments until they are used.
Inspect the integrity of each package.
Open each package aseptically.
Check the chemical indicator to insure that the package has been subjected to the sterilization process.
Step 7 - Quality Assurance Program

An effective quality assurance program that incorporates training, record keeping, maintenance, and use of biological indicators should be in place.
 Training should include:

-     selection and use of PPE when appropriate; 

-     proper use of and interpretation of chemical, multiparameter, and biologic indicators;

-     proper use of all equipment and supplies including sterilizers, cleaners, packaging materials, sealers, cassettes, etc.; 

-     testing of the ultrasonic cleaner.

Record keeping should include sterilization cycle parameters, equipment maintenance, and biologic monitoring results.
Use FDA cleared equipment, supplies, and materials.

Table 2: Heat Sterilization Methods

Method  Precautions

Temperature/ Pressure Exposure Time Advantages Precautions
Steam Autoclave(b) 121C (250F)
(b) 115 kPa 
134C (273F)
276 kPa
13-30 min

3.5-12 min

 

- Good penetration

- non-toxic items 

- Time efficient  

-    Nonstainless steel corrode

-    May damage rubber & plastics

-   Do not use closed containers

-   Unwrapped items quickly contaminated after cycle

Dry heat (c) (oven-type)  160C (320F) 60-120 min 

-     No corrosion 

-     Non-toxic 

-     Items are dry during cycle after cycle 

-     Can use closed container (d) 

 

    Long cycle time

-     May damage rubber & plastic

-     Door can be opened 

-     Unwrapped items quickly contaminated after cycle

 

Dry heat (c)  (rapid heat wrapped transfer)  191C (375F) 12 min: wrapped 

-6 min. unwrapped

-  No corrosion

- Non-toxic

- Time efficient 

- Items dry quickly 

- May damage rubber& plastic 

- May damage rubber& plastic

- Door can be opened during cycle

- Unwrapped items quickly contaminated
after cycle

Unsaturated chemical vapor (b) 134C (273F) 216 kPa  20 min

-  No corrosion

- Time efficient 

- Items dry quickly

 

-     May damage rubber & plastics

 -     Do not use loosed containers

-     Must use special solution

-     Uses hazardous chemical

-     Unwrapped items quickly contaminated after cycle 

(a) These exposure times relate only to the sterilization portion of the total cycle and do not include any warm-up, come-down or drying times. The exposure time may vary depending upon the load and should be verified during actual use by biological monitoring (spor-testing) and the use of chemical indicators.

(b) Monitor with spores of Bacillus stearothermophilus.

(c) Monitor with spores of Bacillus subtilis.

(d) Confirm by using biological indicator on inside of container.


Adapted from: Miller, CH: Update on heat sterilization and sterilization monitoring. Compend Contin Educ Dent 1993; 14:304-316

 

OSAP Position Paper: Instrument Processing: January, 1997

This position paper was developed by the Instrument Processing Working Group of the OSAP Research Foundation. The Instrument Processing Working Group has the following members:

CoChairs: Chris Miller, Thomas Plamondon, Annamaria Phillips, Stephen Spencer Members: Enrique Acosta, Judith Andrews, Carl Cavallaro, Susan Derryberry, Steven Gulbranson, Sharon Gwinn, Robert Hauck, Wendy King, Sandra Laderas, Gayle Macdonald, Claire Pagliara, Mary Quinn, David Resch, Melvin Sawyer, Jeffrey Staples, Dianne Testa, Linda Webster, Kathleen Wolf

 

References

  1. American Dental Association. Infection control recommendations for the dental office and the dental laboratory. J Amer Dent Assoc 127:672-680, 1996.
  2. Association for the Advancement of Medical Instrumentation. Steam sterilization and sterility assurance in office-based, ambulatory care, medical and dental facilities. ANSI/AA MI ST42-1992. Arlington, VA:AAMI, 1992. American National Standard.
  3. Association for the Advancement of Medical Instrumentation. Table-top dry heat (heated air) sterilization and sterilty assurance in dental and medical dental facilities. ANSI/AAMI ST40-1992. Arlington, VA:AAMI, 1992. American National Standard.
  4. Centers for Disease Control and Prevention. Recommended infection control practices for dentistry, 1993. MMWR 42 No. RR-8:4, 1993.
  5. Gooch, B.F., Cardo, D.M. et. al. Percutaneous exposures to HlV-infected blood. J Amer Dent Assoc 126:1237-1242, 1995.
  6. Miller, C.H. Sterilization, disciplined microbial control. Dent Clin No Amer 35:339-355, 1991 .
  7. Miller, C.H. Cleaning, sterilization, and disinfection in dentistry. J Amer Dent Assoc 124:4856, 1993.
  8. Miller, C.H. Ultrasonic cleaning of dental instruments in cassettes. Gen Dent 30:31-36, 1988.
  9. Sanchez, E. and Macdonald, G. Decontaminating dental instruments: Testing the effectiveness of selected methods. J Amer Dent Assoc 126:359-366, 1995.

 

Percutaneous Injury Prevention

 

Background
Exclusions
Conclusions
References

 Introduction

 The goal of this position paper is to describe measures which dental health care workers (DHCW) may use to prevent percutaneous exposures in oral health settings.

 Exclusions

 This position paper does not address the individual steps to manage a percutaneous exposure or individual situations in which an injury may occur. Rather, the emphasis is on skills, behavior and technology (equipment/device design). 

Background

Percutaneous injuries (PIs) pose the single greatest risk of transmission of a bloodborne infection to a dental health care worker in the oral health setting. Percutaneous exposures result from injuries by contaminated needles, burs, scalpels, broken glass, broken capillary tubes, exposed ends of dental wires or other sharps which penetrate or break skin. The prevention of percutaneous injuries is multifactorial and is influenced by equipment design, knowledge, training, skill, technology and an awareness of the consequences potentially associated with an injury. The primary strategies to prevent injuries include appropriate administrative controls such as DHCW education and training and task-specific standard operating procedures with an intent to minimize exposure. Additionally, engineering controls and safer work practice controls may significantly impact the possibility of an injury occurring. Finally, it is imperative to wear the appropriate Personal Protective Equipment to help prevent percutaneous injuries.

Administrative controls affect the largest number of people and are designed to minimize the risk of occupational exposure to blood or other potentially infectious materials. To be effective, assignment of responsibility is critical so that an individual knowledgeable in infection control guidelines and recommendations manages the exposure control and prevention program.

Engineering controls are technology-based and are intended to remove or isolate hazards in the workplace, and include, but are not limited to, rubber dams, needle recappers and sharps containers.

 Work practice controls are behavior-based and involve changing or altering a task or procedure to reduce the likelihood of an exposure. This commitment to safety will greatly influence the success of other control measures.

 It is important to note that recent data from observational and self-reported studies indicate comparable percutaneous exposure (PE) rates among US dentists, oral surgeons, hygienists, and assistants of about 0.3/month (vs. 1 /month dentists in 1987). PIs among dentists are less frequent than among general surgeons and have decreased since 1987, as compliance with universal precautions (e.g., careful handling and disposal of sharps, use of personal protective equipment, etc.) has increased. 

Conclusions

The prevention of percutaneous exposures remains key to minimizing the risk of blood- borne disease transmission. The OSAP Research Foundation encourages:

  1. Practitioners to: communicate the prevention and management of percutaneous exposures to all DHCWs, to train for the safe handling of instruments and devices, to review procedures which may reduce the risk of exposure, and to report and manage all injuries as indicated by OSHA regulations and Public Health Service recommendations.
  2. Educators to: teach the principles and practices of infection control and apply the theoretical information to clinical settings. Further, educators must convey the seriousness of percutaneous exposure and teach avoidance strategies.
  3. Manufacturers to: research and develop safer products, to assist in education, to dialogue with other manufacturers to standardize products and components (i.e., a cassette that fits all instruments and then fits into an ultrasonic and autoclave). Manufacturers and clinicians also need a system of communication as to the needs of clinicians which manufacturers may address.

 Once developed, these interventions need to be evaluated to determine if exposures among DHCWs are reduced, without adverse effects on patient care and safety.

 Manufacturers also should pursue collaboration with educational organizations such as the OSAP Research Foundation.

 The OSAP Research Foundation encourages the use of devices which isolate sharps and discourages inappropriate manipulation of sharps by hand. OSAP encourages research into risk assessment of specific instruments and devices, prioritization of risk product evaluation and other mechanisms for DHCWs to assess the safety of devices. OSAP reminds DHCWs that products have an intended use and that manufacturer's instructions should be reviewed and followed; and in the event of product failure, an immediate report be made to the Food & Drug Administration (FDA).

References

Centers for Disease Control and Prevention Recommended Infection Control Practices for Dentistry, 1993. MMWR. 1993; 42 (No. RR8) 

Cottone, JA, Terezhalmy, GT and Molinari, JA . Practical Infection Control in Dentistry: Second Edition. Published by Williams & Wilkins, 1996.

Cleveland JL, et al. "Percutaneous Injuries in Dentistry: An Observational Study." Journal of the American Dental Association. 126(6):745-751 (1995). 

Department of Labor, Occupational and Safety Health Administration. 29 CFR Part 1910.1030, Occupational Exposure to Bloodborne Pathogens; Final Rule. Federal Register 1991; 56 (235: 64004-182). 

Frontline Health Care Workers: National Conference on Prevention of Sharps Injuries and Bloodborne Exposures, Atlanta, GA, August 14-16, 1995. Co-sponsored by CDC & ACGIH.*

 * The OSAP Research Foundation was one of 13 collaborating organizations in this conference. 

Action Strategies to Prevent Percutaneous Injuries

Administrative Controls

Provide education, training and standard operating procedures. It is critical to assign responsibility so that an individual knowledgeable in infection control guidelines and recommendations manages the exposure control and prevention program.

Example:

 Training, education and standard operating procedures addressing the prevention of occupational exposure to blood and blood contaminated oral fluids should be incorporated 
in the curriculum of dental educational programs
as part of job orientation
as part of ongoing training
Engineering Controls

 Intended to remove or isolate the hazard from the worker.

Examples:

Utilize appropriate sharps containers (puncture-resistant, labeled with a biohazard label or color-coded red, leak-proof on the sides and bottom) and ensure they are located as close to the work area as practical.
Replace sharps containers at sufficiently frequent intervals (when filled to within 1-1.5 inches below the opening) to prevent overfilling. Place used sharps containers in the regulated waste container for disposal.
Close or cover sharps containers when transporting from one place to another.
Incorporate instruments and equipment and operatory layouts that remove or isolate percutaneous hazards.

Work Practice Controls

Reduce the risk of injury by changing the manner in which the task is performed.

Examples:
 Recap anesthetic needles using one-handed scoop technique or mechanical device to hold the needle sheath.
 Minimize uncontrolled movements of sharp instruments under force, such as scalers.
 Use instruments instead of fingers to retract tissues during suturing and anesthetic injections.
 Pass instruments with sharp ends pointing away from all persons.
 Announce passes.
 Maintain appropriate care in the handling and passage of syringes and other sharp instruments.
 Use ultrasonic cleaner, washer/decontaminator, or other effective device to minimize handling during cleanup procedures.
 Use utility gloves during instrument clean-up.
 Use mechanical devices to debride sharps. Two-handed debridement of sharps poses a potential risk for percutaneous injury.

Personal Protective Equipment

 Provide a physical barrier between the body and a source of contamination.

-     Consistently use PPE appropriate to the dental health care worker's tasks and procedures.
-     Train staff on appropriate use, effectiveness and limitations.

Note:    This position paper was developed by the Percutaneous Injury Prevention
      Working Group of the OSAP Research Foundation.

  Dental Unit Waterlines

 

Background  Statement from CDC Regarding Biofilm and Dental Unit Water 
Quality  Backflow Prevention and the Dental Unit  Statements on the Use of Coolant and Irrigating Solutions in Dentistry 
Statements on Methods to Improve and Maintain the Quality of Water Used in Dental Treatment  
Statements on the Responsibilities of Manufacturers of Devices and Chemical Agents for Improving the Quality of Dental Treatment Water  
Statement on the Responsibilities of Clinicians  
Conclusions  
Suggested Procedures for Dental Offices During Boil

-    Water Advisories  

Glossary  
References  
Internet Resources  
Organizational Information

Background

Microbial biofilms are ubiquitous in nature and can be found virtually anywhere there is moisture and a solid surface for attachment [1]. Consisting primarily of naturally occurring, slime-producing bacteria and fungi, biofilms in dental units form on the walls of the small-bore plastic tubing that delivers coolant water for the dental handpieces, sonic and ultrasonic scalers, and air-water syringes used in patient care [2, 3]. Levels of contamination in dental unit treatment water may exceed 1,000,000 colony-forming units per milliliter (CFU/mL). Although bacteria of possible human origin have been reported, most of the organisms recovered from dental unit waterlines occur naturally in aquatic environments.

Although there is no documented epidemiological evidence of a widespread public health problem, the presence in dental waterlines of potential human pathogens (including Pseudomonas aeruginosa [2], Legionella species [4, 5], and non-tuberculous Mycobacterium species [6]) suggests reason for concern. Both altered nasal flora [7] and serological evidence of exposure to Legionella bacteria [8, 9] have been reported in dental healthcare workers. A published case report associated two postoperative Pseudomonas infections in immunocompromised patients with exposure to contaminated dental coolant water [10]. The Occupational Safety and Health Administration (OSHA) has recently alerted its compliance officers of the potential for occupational exposure to bacteria from contaminated dental waterlines [11].

The 1993 Recommendations for Infection Control in Dentistry from the Centers for Disease Control and Prevention (CDC) state that sterile irrigating solutions should be used for all surgical procedures that involve the cutting of bone [12]. In 1995, the American Dental Association (ADA) convened an expert panel to review available information on dental unit waterlines. In December of that year, the Association published a statement on dental unit waterlines that challenged dental equipment manufacturers to produce systems that can reduce the level of bacteria in water used for non-surgical dental treatment to 200 CFU/mL or fewer by the year 2000 [13]. In November 1999, the ADA reaffirmed this goal and reported on scientific and technological developments that had occurred since the panel first convened [14].

Since 1995, there has been significant progress in developing reliable and economical engineering methods to control or prevent the formation of biofilm in dental unit waterlines. To date, the U.S. Food and Drug Administration (FDA) has given clearance-to-market a number of products. When used in a conscientiously applied manner, many of these agents and devices enable dentists to provide high-quality treatment water with minimal impact on dental equipment or materials. These products include chemical agents, independent water reservoirs, automated metering devices and microfiltration technology. Sterile water delivery systems, which employ either heat sterilizable or sterile disposable components, also are available. These systems completely bypass the dental unit. Methods for the clinical monitoring of water quality and compliance with treatment protocols also have been developed. (A current list of FDA-cleared products is available at www.osap.org or through the OSAP Central Office.)

OSAP generally concurs with the CDC and ADA recommendations on the use of coolant and irrigating solutions in dentistry and on the control of microbial contamination in dental unit waterlines. OSAP further urges dentists to take prudent measures to improve the quality of water used for dental treatment. The following statements are intended to assist the dental profession and the dental manufacturing community with a framework for action to improve and maintain the quality of dental treatment water.

Exclusion

Please note that these statements are not intended to serve as a clinical manual for the control of waterline contamination. Dentists should contact the manufacturer of their dental equipment for specific guidance on methods to improve and maintain the quality of dental treatment water.

Statement from CDC Regarding Biofilm and Dental Unit Water Quality

October 1999, Biofilms are microscopic communities consisting primarily of naturally occurring water bacteria and fungi that form thin layers on virtually all surfaces (including dental water delivery systems) that remain in contact with water. The presence of biofilms in dental unit waterlines has been well established. As a result of biofilm formation, relatively high numbers of common water bacteria can be found in some dental water systems. To date, however, scientific evidence indicates there is little risk of significant adverse health effects due to contact with water from a dental unit. Nonetheless, exposing patients or dental personnel to water of uncertain microbiological quality is not consistent with universally accepted infection control principles.

In 1993, the Centers for Disease Control and Prevention issued guidelines relative to water quality in a dental setting. The CDC Infection Control Guidelines for Dentistry state that sterile irrigating solutions should be used when surgical procedures involving the cutting of bone are performed. The guidelines also recommend that all dental instruments that use water (including high-speed handpieces) be run to discharge water for 20-30 seconds after each patient and for several minutes before the start of each clinic day. These recommendations are designed to help reduce the number of microorganisms present in treatment water, but do not appear to reduce biofilm formation in the waterlines.

CDC's 1993 Infection Control Guidelines for Dentistry are currently being updated and will contain more specific guidance for dental unit waterlines. CDC is encouraged by the response of dental equipment manufacturers in developing products to address the issue of dental unit water quality. To date the U.S. Food and Drug Administration has cleared over 25 products designed to improve the quality of water used in dental treatment. Dentists should consult with the manufacturer of their dental unit to determine the best method for maintaining good water quality.

 

Source: Division of Oral Health 
Centers for Disease Control and Prevention

Backflow Prevention and the Dental Unit

The Centers for Disease Control and Prevention (CDC) has been asked by the American Dental Association (ADA), state and local health departments, and local water regulators to provide guidance and scientific information regarding the risk of contamination from cross-connections from dental units. Cross-connections are the links through which contaminated materials may enter a potable water supply system when the pressure of the polluted source exceeds the pressure of the potable source (e.g., during a water main break).

Backflow prevention devices can be used to prevent back-siphonage of contaminated fluids into the public water supply and are regulated by the health authority or the plumbing-code enforcement agencies having jurisdiction. (Note: Anti-retraction valves, used to prevent aspiration of patient materials into some dental handpieces and waterlines, are regulated by the Food and Drug Administration (FDA) and are not considered backflow prevention devices.)

In some locations water regulators have required dental offices to install backflow prevention devices at the service connection or on individual dental units. Many of these requirements appear to be based on two assumptions. First, if a sudden drop in water pressure occurs, oral fluids may be aspirated from a patient's mouth into cross-connected water systems. Second, if aspiration does occur, it may result in a significant risk of transmission of blood-borne viruses from an infected patient to other patients or to persons who are using the same water system. Regulatory interventions requiring the installation of complex, backflow prevention devices in certain dental offices are based on the conclusion that a high degree of hazard of contamination exists. Available science suggests, however, that there is an extremely low risk of such contamination of public water supplies from cross-connections in dental units.

One concern expressed during meetings with local water regulators is the possibility of contamination of public water supplies with bloodborne viruses such as HIV—the virus that causes AIDS. Scientific evidence indicates, however, that the route of transmission of bloodborne viruses is through intimate contact with blood or other potentially infectious body fluids. Transmission of blood-borne diseases has not been reported through the use of any type of water source and is considered highly unlikely. Unlike bacteria or fungi, viruses are unable to reproduce outside a living host and any virus introduced into a water source would be greatly diluted and would probably become noninfectious. Many persons have expressed fear that HIV might be transmitted by contact with wastewater, swimming pool water, and other water sources. Because the hepatitis B virus (HBV), another blood-borne virus, is found in much higher concentrations in blood than is HIV, HBV is considered a more infectious agent. Studies show that the risk of transmission of HBV in sewage and other water is nonexistent; thus, the risk of HIV transmission would be even less.

For a blood-borne infection to be transmitted, four conditions, known as the "chain of infection," must be present:
a susceptible host, or a person who is not immune;  
an opening through which the microorganism may enter the host;  
a microorganism that causes disease; and  sufficient numbers of the organism to cause infection.

The chance of all of these events happening in sequence represents the "risk of infection." Any break in one or more of these "links" in the chain would effectively prevent infection. This information strongly suggests that the risk of transmission of a blood-borne disease through contaminated water supplies is very low.

Possible sites for cross-connection in the dental unit are the cuspidor, high-speed handpiece, and air/water syringe. Today, most dental offices do not use cuspidors and those that are currently manufactured include an air-gap, which prevents backflow. Although a cross-connection is inherent in the design of the high-speed handpiece and air and water syringe, this cross-connection should be considered as very low risk. Both of these devices must have water to operate properly and, when in use, are observed continually by the dentist or hygienist. If water flow is disrupted for any reason, the dental worker would discontinue use of the device. Furthermore, in the unlikely event that a sudden drop in water pressure caused backflow to occur, the volume of aspirated fluid would be minuscule.

Although a theoretical possibility of contamination from cross-connections from dental units does exist, available scientific evidence strongly implies that this risk is nearly zero. Installation of backflow prevention devices, when required, should be consistent with this very low degree of hazard. These suggestions are based on the following:

 HIV is not transmitted by water.  Published evidence of a public health risk due to cross-connections in the dental unit does not currently exist.  The American Water Works Association (AWWA) statement of policy clearly recommends that the installation of backflow prevention devices be consistent with the degree of hazard resulting from cross-connections. Increasingly, dentists are using self-contained dental unit water systems that are not connected to the public water supply.

In addition, the manufacturers' current infection control recommendations and directions for maintenance of each dental unit should be followed. The Oral Health Program at CDC will continue to assess scientific information related to the quality of dental unit water and the safety of patient care delivery.

* "Dental operative unit" refers to the medical device at each dental chair through which water and compressed air flow during dental procedures.

Source: Division of Oral Health Centers for Disease Control and Prevention

Statements on the Use of Coolant and Irrigating Solutions in Dentistry

Statement: The numbers of colony-forming units in water used as a coolant or irrigant for non-surgical dental treatment should be as low as reasonably achievable and, at a minimum, must meet nationally recognized standards for safe drinking water. Non-surgical procedures include most subgingival scaling or restorative procedures as well as initial access into the dental pulp.

Rationale: The 1995 ADA goal encouraged the development of methods to reliably produce dental treatment water that contains fewer than 200 CFU/mL of heterotrophic mesophilic water bacteria. The ADA goal was derived from engineering standards established in the field of hemodialysis, where colony counts higher than 200 CFU/mL have been linked to pyrogenic reactions in patients. This goal remains a viable engineering standard for manufacturers of devices or chemical agents intended to improve the quality of dental treatment water.

The Environmental Protection Agency (EPA), the American Public Health Association (APHA) and the American Water Works Association have set a maximum limit for heterotrophic mesophilic water bacteria in drinking water at 500 CFU/mL [15, 16]. While it is clear that dental water should contain colony counts that are as low as reasonably achievable, there is little scientific evidence that water that meets drinking water standards poses a health hazard for immune-competent individuals. Although procedures within the gingival sulcus may technically expose the vascular system, sulcular tissues are already colonized with microorganisms. The decision to use clean or sterile water during such procedures should be based on the invasiveness of the procedure, the patient's immunologic status, and other potential risk factors for infections, such as infective endocarditis.

Since initial access into the pulp chamber may be performed in conjunction with restorative dental procedures, the use of dental unit water that meets drinking water standards is acceptable for endodontic access procedures, but sterile solutions are preferred for subsequent canal preparation and are required for endodontic surgery.

Statement: Sterile solutions that meet the appropriate standards described in the United States Pharmacopoeia (USP) should be used for all dental procedures that involve the intentional penetration, incision, excision, abrasion, or ablation of intact, nonsulcular oral mucosa to expose normally uncontaminated soft tissue or bone.

Rationale: OSAP concurs with the 1993 recommendation of the CDC that only sterile solutions should be used for surgical procedures that involve the cutting of bone [12]. The OSAP statement further clarifies this position by including all other surgical procedures that expose normally uncontaminated tissues and result in penetration of the vascular system. The USP sets standards for sterile solutions that assure that they are free of viable microorganisms and have acceptably low levels of bacterial endotoxin and other potentially harmful substances [17].

Statements on Methods to Improve and Maintain the Quality of Water Used in Dental Treatment

Statement: OSAP cautions that flushing waterlines for several minutes prior to beginning dental treatment without additional treatment to remove or suppress microbiologic contamination should be used only as an interim measure until more effective methods can be applied. The practice of briefly flushing waterlines between patients to remove patient material potentially retracted during treatment as recommended by the CDC should be continued.

Rationale: The efficacy of mechanical flushing alone to control microbial contamination in dental unit water is not well supported by the scientific literature. Although flushing can temporarily reduce the number of organisms suspended in dental waterlines, there is no predictable effect on adherent biofilms. Bacterial aggregates breaking free from the biofilm have been shown to re-contaminate dental unit water during the course of subsequent clinical treatment [18, 19]. Flushing for several seconds between patients, however, may remove materials that may have entered the water system during patient treatment [12].

Statement: Devices that provide surgical irrigation in the oral cavity must use sterile, non-pyrogenic reservoirs or tubing for solutions that enter the surgical site. All components of this pathway must be single-use disposable or compatible with heat sterilization methods used in outpatient dental settings. Manufacturers should test all reusable devices to validate the efficacy of recommended sterilization procedures.

Rationale: Examples of devices covered by this statement include oral surgery and implant handpieces, sonic and ultrasonic scalers used during periodontal surgery, and surgical irrigation devices such as bulb syringes. Use of sterile, non-pyrogenic tubing and reservoirs for surgical coolant or irrigants assures that these solutions meet standards of care for surgical procedures. Acceptable sterilization methods should include steam autoclaves or alcohol/formaldehyde chemical vapor sterilizers.

Statements on the Responsibilities of Manufacturers of Devices and Chemical Agents for Improving the Quality of Dental Treatment Water

Statement: OSAP discourages the use of low-temperature water-heating systems in dental units because of their potential to increase the numbers and/or pathogenicity of waterline microorganisms.

Rationale: Low-temperature dental-unit-water heaters are designed to maintain dental treatment water at or near human body temperature. This may stimulate bacterial proliferation and could select organisms pre-adapted to growth at body temperature. Water in separate reservoir systems that are maintained at room temperature can provide adequate patient comfort while discouraging the growth of potential human pathogens. Chemical agents used for waterline treatment also may damage water heaters.

Statement: Manufacturers of devices and solutions marketed for the control of microbial contamination in dental unit water systems are responsible for validating the safety and efficacy of products and obtaining appropriate regulatory clearance or registration.

Rationale: Untested devices and protocols may be ineffective or potentially harmful to patients, dental healthcare workers, and dental equipment. Dental equipment manufacturers are legally and ethically obligated to ensure the safety and efficacy of devices that claim to improve the quality of water used in dental treatment.

Statement: Commercial devices and chemical agents marketed for the control of microbial contamination in dental unit water systems should be cleared for market by the FDA and/or registered with the EPA as appropriate. A fully workable process to accomplish this does not presently appear to exist. Therefore, both FDA and EPA should work with professional organizations, the dental industry, and standards-setting bodies such as the American National Standards Institute (ANSI) to develop a workable strategy for clearance or registration of products intended to improve and maintain the quality of dental treatment water.

Rationale: The FDA classifies dental water treatment and delivery systems as medical devices subject to pre-market clearance requirements under the Federal Food, Drug, and Cosmetic Act (FD&C). The FDA also must clear-for-market chemical agents that are continuously present in dental treatment water. As a result of congressionally mandated agreements between the two agencies, all other chemical germicides with dental waterline claims now must be registered with the EPA as directed by the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). OSAP is aware that the neither EPA nor FDA presently have adequate regulatory processes for this commercial application. This regulatory impasse has created much confusion among dentists and the dental industry and serves to discourage the development, marketing and use of safe and effective products.

Statement: The manufacturers of chemical agents must supply Material Safety Data Sheets and other pertinent information as required by OSHA.

Rationale: Chemical agents used for the control of microbial contamination of dental treatment water must be safe for patients and healthcare workers when used as directed. Furthermore, if the chemical agent is not completely removed, it must leave only safe levels of residues in dental treatment water. All chemicals used in dental unit water systems must comply with all applicable federal and state occupational health and safety requirements.

Statement: Chemical agents that are continuously present in dental water supplies or that leave detectable residues should be compatible with dental restorative materials. In order to claim that an agent has no effect on dental materials, manufacturers should perform appropriate testing and inform users if the water-treatment solutions may be incompatible with specific dental restorative materials.

Rationale: Chemical agents and residues present in dental treatment water may have unintended effects on dental restorative materials. Studies have been published suggesting that some products may contain substances that can interfere with dental adhesive materials [20, 21].

Statement: Devices and chemical agents commercially marketed for the control of microbial contamination in dental unit water systems should be compatible with the materials used in the construction of the dental units. Manufacturers should perform appropriate compatibility testing with commonly used dental unit waterline materials and must inform users if devices or solutions may be incompatible with dental delivery systems.

Rationale: Chemical agents may have unintended effects on materials used in the construction of dental water delivery systems and may damage components or produce potentially hazardous disinfectant byproducts [22]. This concern is most acute for devices or chemical agents that may be used on a wide variety of dental units.

Statement: Dental unit water systems must be designed to prevent retraction of patient material to the maximum extent possible. Manufacturers should provide instructions for periodic testing, maintenance, or replacement of components intended for this purpose.

Rationale: Retraction of patient material by dental water systems offers the potential for patient-to-patient transmission, either directly or by permitting colonization of waterline biofilms by organisms from the oral cavity. There is evidence that the performance of anti-retraction devices—whether active or passive—may degrade over time [23]. Manufacturers should be aware of the limitations of the devices installed on their dental units and provide users with appropriate guidance to maintain optimal performance.

Statement: All devices and solutions marketed for the purpose of improving, maintaining, or monitoring the quality of dental treatment water must have clearly written precautions and instructions for installation, use, and maintenance. Ideally, devices and protocols should be designed to minimize user intervention.

Rationale: Treatment methods for the control of microbial contamination of dental treatment water may be technique-sensitive. Simple, well-written instructions can greatly enhance the probability of clinical success and reduce the potential for damage to equipment or injury to staff or patients. Greater automation of procedures can save time and decrease the potential for human error.

Statement: Manufacturers of devices and chemical agents for improvement of dental water quality should use validation studies to develop outcome measures and manage-ment tools for clinical monitoring. Clinical monitoring is a quality-assurance process and is not intended to re-validate process efficacy. Microbiologic methods should be consistent with recognized standards for measurement of heterotrophic water bacteria [16, 24].

Rationale: Since manufacturer-recommended treatment methods should be validated by laboratory and clinical studies prior to marketing, the primary purpose of monitoring should be to identify technique errors or non-compliance. Because non-compliance has been identified as an important cause of clinical failure, monitoring also can provide a positive-reinforcement feedback loop for the dental staff [25]. Use of the heterotrophic plate count (HPC) or other scientifically validated methods can be correlated with the assessment methods used by public health authorities to test drinking water.

Statement: Routine testing for specific organisms such as Legionella or Pseudomonas is not recommended. Such testing should only be performed to investigate a suspected waterborne illness as directed by local health authorities.

Rationale: Just as there is little need to culture environmental surfaces or instruments following disinfection and sterilization procedures, there are few reasons to routinely test for potential pathogens such as Legionella or Pseudomonas in dental unit water, since most treatment methods target the entire biofilm, rather than specific organisms. Current CDC guidelines do not recommend routine environmental testing in healthcare settings [26]. A negative test for a difficult-to-culture pathogen such as Legionella at a given point in time may give false reassurance of the safety of dental treatment water. Unless a different treatment regimen will be used when specific organisms are recovered, there is no need for such testing. The documented isolation of pathogenic organisms from dental water systems also may have medico-legal implications for the dental practice.

Statement on the Responsibilities of Clinicians

Statement: Dental practices should immediately take prudent measures to provide quality water for dental treatment and ensure a safe and healthy environment for patients and staff. OSAP recommends that all practicing dentists take the following steps:

  1. Review the scientific literature to gain an understanding of the nature and potential risks associated with dental waterline contamination.
  2. Contact the manufacturer of dental units and other devices that use water to obtain current recommendations on how to maintain the quality of dental treatment water.
  3. When replacing dental units and devices, select products that can economically and reliably maintain water quality.
  4. When purchasing new units, retrofit devices, or solutions, obtain relevant information from the manufacturer on the safety, efficacy, and cost effectiveness of each product.

Rationale: The use of water for dental therapeutic procedures that fails to meet established standards for drinking water is inconsistent with recognized standards of infection control and can potentially undermine public confidence in the dental profession. The present lack of epidemiologic evidence of illness or injury among patients or dental healthcare workers does not provide a valid rationale for inaction.

Conclusions

Scientifically validated treatment methods are currently available to permit delivery of dental treatment water of acceptable microbiologic quality with minimal risk to patients, staff, and dental equipment. To best ensure the health and safety of dental patients and staff, manufacturers of dental equipment, devices, and chemical agents intended to improve and maintain the quality of dental treatment water should base their efforts on a strong foundation of peer-reviewed science. Federal regulatory agencies must develop workable clearance and registration processes to help ensure the safety and efficacy of products intended to maintain or improve the quality of dental treatment water. OSAP believes that these goals can best be accomplished by collaboration among government agencies, industry, academia, and clinicians. OSAP and other professional organizations must encourage an aggressive research agenda on this issue and continue their efforts to educate the dental profession.

Suggested Procedures for Dental Offices During Boil-Water Advisories

The Division of Oral Health, which is part of the National Center for Chronic Disease Prevention and Health Promotion at the Centers for Disease Control and Prevention (CDC), suggests that the following procedures may be appropriate for dental offices during boil-water advisories. These procedures should be observed in addition to specific instructions issued by state or local health departments during these advisories.

While a boil-water advisory is in effect:

 Water from the public water system should not be delivered to the patient through the dental unit*, ultrasonic scaler, or other dental equipment that uses the public water system until the boil-water advisory is canceled.  Patients should not use water from the public water system for rinsing but should use water from alternative sources, such as bottled or distilled water.  Dental workers should not use water from the public water supply for hand washing. Instead, antimicrobial-containing products that do not require water for use, such as alcohol-based hand rubs, can be used until the boil-water notice is canceled. These products have been reviewed and cleared for marketing by the U.S. Food and Drug Administration (FDA).

When the boil-water advisory is canceled:  First, incoming public water system water lines in the dental office should be flushed (i.e., cleared of contaminated water). All faucets in the dental setting should be turned on completely for at least 30 minutes, including water lines to dental equipment that uses the public water system. After the incoming public water system water lines are flushed, dental unit water lines should be disinfected. The dental unit manufacturer should be consulted to determine the appropriate procedures to disinfect the dental unit water lines.

Because water from the affected public system should not be delivered to the patient during a boil-water advisory, many dental procedures cannot be performed. Alternative water sources, such as separate water reservoirs that have been cleared for marketing by the FDA, can be used. However, if the alternative water source were to flow through a dental unit previously connected to the affected public water supply, the dental unit water lines should first be flushed and disinfected according to the manufacturer's instructions.

* "Dental unit" refers to the medical device at each dental chair that provides water and compressed air for the use during dental procedures.

 

 Source:   Division of Oral Health
    Centers for Disease Control and Prevention
    Aug. 30, 2001

Glossary

Adhesion/attachment A stable interaction of a cell with respect to a surface. Living cells actively excrete holdfast chemicals from their surface to anchor themselves to a substratum.

Antimicrobial agent An agent that kills or inhibits microbial growth. May include materials also described as biocides, disinfectants, or germicides. Use and definitions of these terms may be further specified in certain federal regulations or statutes (although neither FDA nor EPA currently recognizes these terms as legal for claims regarding dental unit water systems).

Biofilm Slime-producing bacterial communities that also may harbor fungi, algae, and protozoa. These microorganisms colonize and replicate on the interior surfaces of waterline tubing, creating adherent microbial accumulations.

Biocide An agent capable of killing microorganisms; however, it may not be 100% effective. In biofilm usage: A chemical used to disinfect or remove biofilm in order to control a detrimental effect of the biofilm. See also antimicrobial agent, disinfectant, germicide.

Chemical disinfectant as defined in current FDA documents A chemical agent that eliminates a defined scope of pathogenic organisms, but not necessarily all microbial forms (e.g., bacterial endospores). (Rutala, 1990)

Colony-forming unit abbr. CFU The minimum number of separable cells on the surface of or in semi-solid agar medium which gives rise to a visible colony of progeny on the order of tens of millions of cells in number. CFUs may consist of pairs, chains, and clusters as well as single cells and are often expressed as colony-forming units per milliliter (CFU/mL).

Dental treatment water Non-sterile water used for dental therapeutic purposes, including irrigation of non-surgical operative sites and as a coolant for highspeed and ultrasonic instruments.

Dental unit waterlines (DUWL) Small bore tubing, usually made of plastic, used to deliver dental treatment water through a dental unit.

Disinfection as defined in current FDA documents The destruction of pathogenic and other kinds of microorganisms by thermal or chemical means. Disinfection is a less lethal process than sterilization, since it destroys most recognized pathogenic microorganisms, but not necessarily all microbial forms, such as bacterial spores.

Disinfection processes do not ensure the margin of safety associated with sterilization processes. (AAMI/Association for the Advancement of Medical Instrumentation, 1995)

Drinking water as defined by EPA microbiologic standards The Surface Water Treatment Rule includes the following limits on microbial contaminants in surface water or ground water under the direct influence of surface water:

 Giardia lamblia: 99.9% killed/inactivated  Viruses: 99.99% killed/inactivated  Legionella: No limit, but EPA believes that if Giardia and viruses are inactivated,  Legionella also will be controlled.  HPC: No more than 500 bacterial colonies per milliliter.  No more than 5.0% samples total-coliform-positive in a month. All total-coliform-positive samples must be analyzed for fecal coliforms. There cannot be any fecal coliforms. (Fecal coliforms and Escherichia coli indicate that water may be contaminated with human or animal wastes that can cause diarrhea, cramps, nausea, headaches, or other symptoms.)

Germicide as defined in current FDA documents An agent that destroys micro-organisms, especially pathogenic organisms. Other categories of agents that use the suffix "-cide" (e.g., virucide, fungicide, bactericide, sporicide, tuberculocide) destroy the microorganism identified by the prefix. (Block, 1991) See also antimicrobial agent, biocide, disinfectant.

Glycocalyx Extracellular polymeric material produced by some bacteria. The term was initially applied to the polysaccharide matrix excreted by epithelial cells forming a coating on the surface of epithelial tissue. A general term for polysaccharide compounds outside the bacterial cell wall, it also is called slime layer, extracellular polysaccharide (EPS), or matrix polymer.

Heterotrophic bacteria Those bacteria that require an organic carbon source for growth, i.e., they derive energy and carbon from organic compounds. The modifier "mesophilic" is used to describe bacteria that grow best within the middle ranges of environmental temperature.

Heterotrophic plate count bacteria abbr. HPC bacteria Those bacteria that can be grown on non-selective heterotrophic medium plates.

Independent water reservoir A container used to hold and supply water or other solutions to handpieces and air water syringes attached to a dental unit. The independent reservoir also isolates the unit from the public water system. May be provided as original equipment or as a retrofit device on all modern dental units.

Medical device as defined by the Food, Drug, and Cosmetic Act An instrument, apparatus, implement, machine, contrivance, implant, in vitro reagent, or other similar or related article, including any component, part, or accessory that is (1) recognized in the official National Formulary, the United States Pharmacopoeia, or any supplement to the aforementioned; (2) intended for use in the diagnosis of disease or other conditions, or in the cure, mitigation, treatment, or prevention of disease in man or animals; or (3) intended to affect the structure or any function of the body of man or other animals, does not achieve its primary intended purposes through chemical action within or on the body of man or other animals, and is not dependent upon being metabolized for the achievement of any of its principal intended purposes.

Microfiltration Use of membrane filters to trap microorganisms suspended in water. In dental usage, filters are usually installed on dental unit waterlines near the point of use as a retrofit device. Microfiltration commonly occurs at 0.03 to 10 microns (micrometers). Sediment filters commonly found in dental unit water filter regulators range from 20 to 90 microns and do not function as microbiological filters.

Retraction The entry of oral fluids and microorganisms into waterlines as a result of negative water pressure or other hydrodynamic processes. Also referred to as "suck-back."

Sterile as defined in current FDA documents The state of being free from all living microorganisms; in practice, usually described as a probability function, e.g., as the probability of a surviving microorganism being one in a million. (AAMI, 1995)

Sterile water for irrigation Water described in an official monograph in the current U.S. Pharmacopoeia with various specifications, including limits on pyrogens (bacterial endotoxin) and other impurities. "Sterile water for irrigation" is a "finished" product that is packaged and labeled for non-intravenous use in surgical irrigation.

References

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Internet Resources

American Dental Association, Statement on dental unit waterlines, 1995, http://www.ada.org/prac/position/lines.html

Centers for Disease Control and Prevention. Recommended Infection-Control Practices for Dentistry, 1993; MMWR 42(RR-8) http://www.cdc.gov/epo/mmwr/preview/mmwrhtml/00021095.htm

Center for Biofilm Engineering, Montana State University. Interdisciplinary glossary, 1999, http://www.erc.montana.edu/Res-Lib99-SW/glossary/Gterms.html

Environmental Protection Agency, National Primary Drinking Water Regulations, 1999, http://www.epa.gov/OGWDW/wot/appa.html

Occupational Safety and Health Administration. OSHA Technical manual TED 1-0.15A, 1999, http://www.osha-slc.gov/dts/osta/otm/otm_toc.html

Organizational information

OSAP is a group of dentists, auxiliary staff, allied health professionals, government representatives, industry members, academicians, and researchers devoted to advancing the art and science of dental infection control and practice safety. A clearinghouse of information on dental asepsis and safety issues, OSAP works to educate the dental community through its publications, annual symposia, and web site (www.osap.org). For additional information on the organization and the efforts of its educational foundation, contact OSAP at 800-298-6727.

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